BIOLOGICAL BASIS OF BEHAVIOR
Psychology 321
Spring, 2005 HGH 225
Dr. John M. Morgan MWF, 8am to 9:00
Samara Miles-Prystowsky
Biological Basis of Behavior
Introduction to Cerebellar Lesions
March 2005
Introduction: The Cerebellum
The Cerebellum, accounting for approximately 25 percent of
the brain, sits above the brainstem and communicates with nearly
all areas of the neuroaxis. It is implicated in sensory, motor,
cognitive, emotional and speech processing, display
neuroplasticity, learning, and memory. (Joseph, 2000.) The
cerebellum is made up of several structures, and differing
regions have different functions with a primary motor component,
including visual processing, speech, and the visual guidance of
movement (Joseph, 2000). Its main function continues to be
“stabilizing the body and providing information about the
position and movement of the head in relation to gravity”
(Joseph), as well as coordination of axial and appendicular
(trunk and limb) muscles, which takes place in the anterior
lobes. The neocerebellum (the dentate gyrus and cerebellar
hemispheres) evolved to coordinate upper/lower limb movements
and gait. It is the neocerebellum that controls multiple joint
and voluntary movements, and is indicative of fine motor skills
and the resulting learned, then automatic, behavior.
Appearing homogenous, the cerebellum is made up of a
three layered cortex “which overlays and communicates with three
pairs of deep cerebellar nuclei: the dentate, fastigious, and
interpositus” (Joseph). It is further structurally and
functionally divided up into the anterior lobes, posterior
lobes, and flocculonodular lobes. The cerebellar body is divided
into the archicerebellum (including the flocculonodular lobe),
the paleocerebellum (aneterior lobe) and, lastly, the
neocerebellum, so influential in motor, somatic, and cognitive
activity. Thus, the cerebellum is rich in cognitive activity
and information transmission.
Marchele Robbins
Bio Basis of Psychology
March 2005
Cerebellum
The hindbrain is the posterior part of the brain that
consists of the medulla oblongata, the pons and the cerebellum.
The cerebellum is located posterior of the brain and is fist
size in structure. The cerebellum is a large part of the
hindbrain structure that has many deep folds. One of the major
functions of the cerebellum is its contribution to the control
of motor movements, balance and coordination. The cerebellum
can be considered as a computer because of its ability to convey
messages to different parts of the brain. The Cerebellum
contains most of the neurons within the brain. It is connected
to the cerebral cortex by 40 million nerve fibers which allow it
to process messages quickly to different regions in the brain.
It receives a large amount of its information from the “higher”
brain function also know as the cerebral cortex and the
cerebellum receives speech and rational thought messages from
the cerebral cortex as well. The 40 million nerve fibers make
up what is known as the optic nerve and its function is to
transmit visual information that is seen through the eyes.
“Forty times that much information can be sent from the cerebral
cortex down to the cerebellum, including information from
sensory areas of the cerebral cortex, from motor areas, from
cognitive areas, from language areas, and even from areas
involved in emotional
functions“(www.newhorizons.org/neuro/leiner.htm).
The cerebellum processes and conveys information through
its hardware and software system via the brainstem. The
hardware of the system is the “circuitry” which can be
considered as the cerebellum and the software of the system is
the messages that are sent through the circuitry which is the
cerebral cortex.
This picture shows how information is processed from the
cerebral cortex to the cerebellum. The cerebral cortex acts as
a conductor that sends linguistic, cognitive, sensory and motor
information along the brainstem to the cerebellum.
The Cerebellum is an important part of the motor system.
It relies on different parts of brain to give it specific
functions to carry out. The medial part of the cerebellum
participates in control of the ventromedial system. The
ventromedial system has four tracts which are the
vestibulospinal tract, tectospinal tract, pontine (medial) tract
and medullar (lateral) reticulospinal tract. Each tract lies
along a different area of the brainstem which allow it to help
carry out the motor functions of the cerebellum.
First off the ventromedial system contributes to postural
control and some reflexive movements. The first tract is the
vestibulospinal tract which is primarily responsible for the
information it receives from the inner ear and it also helps the
head maintain its position parallel to the shoulders. This is
important while walking and trying to look in any direction.
The tectospinal tract receives a small amount of visual
information from the retina. The pontine tract and the
reticulospinal together actively help maintain posture. The
vestibulospinal and reticulospinal influence the vermis. The
vermis is the middle part of the cerebellum between two
hemispheres and receives visual and auditory information. The
lateral zone of the cerebellum helps in the control of
independent limb movement and skilled movements. These
movements are produced by the frontal cortex and motor cortex.
The frontal and motor cortex send information on intended
movements to the lateral zone of the cerebellum through the
pontine tract.
A healthy cerebellum is crucial for the development and
maintenance of posture, balance, subconscious motor control, and
fine coordination. The cerebellum seems very important and
without it many different connections would fail thus resulting
in no body movements. It may be possible to actively think
about moving or picking up an object, but with a systematic
malfunction no movement will be achieved. Some people would
describe this state as cerebellar damage. When the cerebellum
is damaged or its pathways disrupted then subconscious,
automatic movements are reduced or lost. Some may experience
Mild Cerebellar Dysfunction, which is the inability to judge the
range of limb movements without watching them. Severe
Cerebellar Dysfunction which is the inability to perform limb
movements smoothly and efficiently even while watching them.
There are also Cerebellar Function Disorders which are Asthenia,
Ataxia, Dysmetria and Fatigability. Asthenia and Ataxia are
alike in that their primary basis causes a lack of muscular
strength or muscular incoordination. Dysmetria is a failure to
stop a motion at the intended point, an example of this would be
the finger to nose test. Fatigability is muscles on the same
side, where cerebellar damage has occurred, tire more easily and
have slower than normal contraction which results in slowed
movements (www.disabled
world.com/artman/publish/glossary.shtml).
It is clear that we know what can occur from having damaged
the cerebellum, but what causes damage to the cerebellum?
According to The Merck Manual of Medical Information online it
states,” Prolonged alcohol abuse is the most common cause of
damage to the cerebellum” (www.merck.com/mmhe.html). Other
causes may include strokes, tumors, hemorrhage to the brain,
repeated head injuries, birth defects of the brain, multiple
sclerosis, and toxic chemicals such as carbon monoxide and heavy
metals just to name a few and all are forms of cerebellar
lesions.
Many people suffer from strokes at least once in their life
time. A stroke can be defined as an interruption of the blood
supply to any part of the brain, resulting in damaged brain
tissue. People who have suffered from strokes were more likely
to have experienced anger or negative emotions in the two hours
prior to the stroke. Also people were likely to have experienced
sudden changes in body position in the before having a stroke.
In a study conducted by Fabbro, Tavano, Corti, Bresolin, De-
Fabritiis and Borgatti looked at the long term
neuropsychological deficits after cerbellar infarctions in two
young adult twins. The study featured two young adult dizygotic
twins who suffered two strokes at the ages of 26 and 30 years.
Each twin was identified as case 1 and case 2. Case 2 suffered
a stroke a few months after case 1 at age 30 and then case 1
suffered a second stroke a few months later. Case 1 suffered
from lesions in left cerebellar hemisphere in both stroke
episodes. As for case 2 she suffered lesions from the right
cerebellar hemisphere in the first stroke, but in several
cerebellar hemispheres in the second stroke. Both twins fully
recovered from the strokes seven years later and had no
complications in motor functions; however the twins still had
slight linguistic complications. Such as comprehension, reading
and writing and agrammatism which is an inability to put
together a grammatical sentence while retaining the ability to
speak words. They also experienced dysfunction in visuospatial
short term memory.
References
Fabbro, F; Tavano, A; Corti, S; Bresolin, N; De-Fabritiis, P;
Borgatti, R, (2004). The Long-term neuropsychological deficits
after cerebellar infarctions in two young adult twins. Journal
of Neuropsychologia.2004; Vol. 42 (4): 536-545.
Information on Cerebellar disorders. Retrieved April 2005.
Available at
http://www.disabledworld.com/artman/publish/glossary.shtml.
Information on the causes of cerebellar disorders. Retrieved
April 2005. Available at http://www.merck.com/mmhe.html
The Treasure at the Bottom of the Brain. Retrieved April 2005.
Available at http:// www.newhorizons.org/neuro/leiner.htm
Carlson’s Movement: The cerebellum. Information on cerebellar
dysfunctions. Retrieved April 2005. Available at
http://nawrot.psych.ndsu./cerebellumhtml.
Dean Chelossi
Biological Basis of Behavior
Neurosurgeon Perspective
March 2005
Cerebellar Lesions and The Neurosurgeon
Modern Surgical Approaches
The incorporation of computed topography into stereo
tactic techniques coincided with a general interest in stereo
tactic approaches to intracranial tumors. Several authors
including Moser and Backlund in 1982 and Apuzzo in 1984 reported
safe CT based stereo tactic tumor biopsies ofpineal region
tumors. Most series of stereo tactic tumor biopsies contain a
number of pineal region lesions. The reported mortality and
morbidity of imaging based stereo tactic biopsy is very low. It
is now clear that stereo tactic biopsy is one option in a
management of a pineal region tumor. However, the question of
sampling is frequency raised. In addition, many pineal region
tumors are not cured with radiation and chemotherapy and need to
be resected.
Open Approaches
The evolution of modern microsurgical techniques have
resulted in a precipitous reduction in the morbidity
andmortality in the open approaches for the excision of pineal
tumors. Packer (1984) reported no
mortality in the partial resection of 24 pineal region tumors
most of which were operated using a transcallosal approach,
although an infratentorial approach was use d in some of these.
Larger subsequent
series were reported by Lapras and Patet (1987) with 100
patients and no mortality and Sano (1987) with 125 patients.
Edwards (1988) and Hoffman (1991) each reported pediatric series
of 30 and 33 patients respectively.No mortality was experienced
in any of these surgical series. Most employed infratentorial or
transtentorial approaches. The open approach has two major
advantages over stereo tactic biopsy: it provides more tissue
and adequate histological sampling and it allows excision of
tumors, which can potentially cure by resection.
Stereotactic Biopsy
The surgical methods are reported elsewhere and described
briefly here.Stereo tactic biopsies were performed utilizing the
COMPASS stereo tactic system (COMPASS international, Inc.
Rochester, Minnesota). The procedures comprise three steps: data
base acquisition, surgical planning and thesurgical procedure.
Data base acquisition: Under sedation and local anesthesia
a CT/MRI compatible stereo tactic head frame is placed. This
attaches to the patient’s skull by means of 4 flanged carbon
fiber pins inserted through twist drill holes through the outer
table of the skull into the diploe. Micrometers are used to,
easier the length pf the foxed length carbon fiber pin which
extends beyond the vertical supports of the stereo tactic head
frame. The micrometer measurements and osseous fixation provide
a mechanism by which the frame can be applied, removed and
reapplied if data
acquisition and surgery are planned for two different days
subsequent stereo tactic procedures are planned.
Patients then undergo CT, MRI and Digital Angiography’s
(DA), which are performed with imaging modality specific
localization systems for each.
These create reference marks on each image for stereo tactic
coordinate calculation and imaging cross registration. For
pineal region tumors DA
comprises arterial and venous phase examinations of both carotid
arteries and one vertebral artery. Data is transferred from the
CT, MRI and DA hostcomputers to the operating room computer
system.
Surgical Planning: On the operating room computer display
monitor the surgeon reviews the CT and MRI images, which depict
the lesion. The reference fiducially on the imaging studies is
digitized. This allows thecomputer to suspend all of the CT, MRI
and DSA images in a three dimensional image matrix within the
computer memory. The surgeon selects a target point within the
pineal tumor on the display monitor and the commuter calculates
the stereo tactics frame coordinates, which place this pint into
the focal point of the arc-quadrant stereo tactic frame.
The trajectory is then planned. Pineal tumors are
approached from anterior and lateral in order to avoid the
internal cerebral veins and the basilar veins of Rosenthal as
well as surface vessels. In general this usually turns out to be
about 40 degrees from the axial plane (collar angle) and
40degrees from the sagittal place (arc angle). This trajectory
is displayed on the DA images on the computer monitor and may be
adjusted by the surgeon. The trajectory may also be viewed on
sequential CT or MRI slices. It is important to note that the
biopsy specimen wills b obtained utilizing a 1-center minter
window type biopsy cannula of the type decribed by Sedan. In
reviewing the trajectory it is important to have
that window totally within the tumor and no part of the window
extending into third ventricle (where aspiration on the cannula
will retrieve only ventricular fluid) or extending posterior to
the tumor (where the risk of bleeding into the subarachnoid
space exists).
Surgical Procedure: Stereotactic biopsy is performed under
general anesthesia. A 3mm diameter cranial opening is made by
twist drill is directed by the Stereotactic arc-quadrant through
a stab incision on the scalp, the dura is opened by unplug
electrocute delivered to a insulted probe and the Sedan biopsy
throchar with a 1 centimeter window is directed to the target
point. Several biopsy specimens may be obtained by rotating the
window of the cannula for each specimen. Serial specimens can be
obtained in large tumors. The position of each specimen is
confirmed by
anteroposterior and lateral collimated teleradiographs. A small
piece of the surgical specimen is placed on glass slides for H&E
stained smear preparations and the remainder of the specimens
are for formalin fixed permanent sections.
Stereotactic Third Ventriculostomy
This procedure is performed in patients with obstructive
hydrocephalus as alternative to shunting. Stereotactic targets
are selected from the steorotachic CT scan in the intrpeduncular
cistern I the midline, midway between the basilar artery and the
dorsum sellae and in the foramen of Monro. A ventriculoscope is
directed by the stereo tactic frame through a frontal burr hole
through the foramen of Monro through the floor of the third
ventricle to the target point in the intrpeduncular cistern. The
opening in the floor of the third ventricle is enlarged by a
leukotome. CSF flow from third ventricle into intrpeduncular
cistern is confirmed by radioisotope ventriculogram or GRASS
sequence on MRI.
Stereotactic Cyst Aspiration/ Instillation of P32
Unrestricted cystic tumors are managed by Stereotactic
aspiration of the cyst contents. To prevent recurrence the
stereo tactic instillation of
Beta emitting colloid P32 into the cyst cavity is used to
deliver a selective high radiation dose to the secreting walls
of the cyst. Following delivery of the desired radiation dose
level, the cystic contents and P32 are stereo tactically
aspirated and a subsequent procedure.
Open Resection
The infratentorial, supracerebellar approach is utilized
for the majority of pineal region tumors. The patient is placed
in the sitting position. A right atrial catheter and Dopper
monitor to detect air remobilization are employed. The scalp is
opened with a midline incision and a sub occipital craniotomy
performed which includes the foramen magnum. This wide bone
exposure allows the cerebellum to settle inferiority; opening
the space between the superior aspect of the cerebellum and the
tantrum - no retraction to depress the cerebellum and the
tentorium – no retraction to depress the cerebellum is ever
necessary. The dura is opened in a “Y” shaped fashion and the
cistern magna is incised to allow cerebrospinal fluid to escape.
The cerebellum bellum then sinks inferiorly and stretching
of the bridging veins between the superior aspects of the
cerebellum is noted. All of these are identical coagulated and
cut. The cerebellum sinks more inferiority and this exposes the
posterior mesencephalic arachnoid and cisterns, which are opened
widely. This exposes the precentral cerebella vein, which must
be coagulated and cut to gain exposure of the pineal region.
In most pineal tumors it is best to establish a plane
around the tumor before attempting to “debulk” it. Coagulation
of the surface of the tumor with bipolar forceps frequently
causes capsule to contract away from the brain parenchyma and
this opens a plane between tumor and parenchyma. It is best to
establish the plane laterally and them separate the lesion off
the rostra brainstem and floor of the third ventricle and the
internal cerebral veins.
In many cases the tumor can be isolated and removed as a
single intact specimen. This keeps bleeding to a minimum and
allows development of a clean plane around the tumor and a gross
total resection of most lesions.
Clinical Material
The present series comprises 49 patients (34 miles and 15
females; age range 6 to 73 years) with pineal region neoplasm
operated between August 1984 and September 1992. The firm tissue
diagnosis was established by stereo tactic biopsy or craniotomy
in all of the patents. Stereotactic biopsy provided the
diagnosis in 35 of 37 cases. Both of the patients in whom stereo
tactic biopsy failed to provide the diagnosis underwent
subsequent craniotomy.
Neoplasms were found in 41 of the 49 patients. Of these, 28
patients had malignant lesions, 13 patients had benign lesions.
There were 14 gliomas, 11 germ cell tumors (germinomas in 8
patients, yolk sac tumors in 2 patients and malignant teratoma
in one patient), 10 pineal parenchyma tumors and 8 misc lesions
(4 benign and 4 malignant). There were eight (8) non-neoplastic
lesions: 5 pineal cysts, 1 arachnoid cist, 1 inflammatory lesion
and 1 thrombosed arteriovenous malformation.
Oncoproteins
Oncoproteins in lumbar CSF showed elevation of Human
Chronic Gonadotropin (HCG) in only one of 8 patients harboring
germinomas. Alpha-fetoprotein was elevated in 2 patients with
yolk-sac tumors and in one patient with malignant teratoma.
CT and MRI appearance
In general there were six (6) separate tumor configuration
on CT and MRI; none of these were universally characteristic of
a particular histological type over another:
Type A:
Uniform enhancement with speckled calcification (16
patients). This configuration is typically associated with
germinomas and was, in fact noted in 8 germ cell tumors (7
germinomas, 1 solid yolk sac tumor) in our series. However, 4
pineal parenchymal tumors, 1 meningioma, 1 thrombosed AVM, 1
inflammatory lesion also had this appearance.
Type B:
Uniform contrast enhancement (13 patients). This
configuration was noted in 5 pineal parenchymal tumors as well
as in 4 gliomas, 1 germinoma, 1 meningioma, and 1 lymphoma and
on malignant tumor of unclear cell type.
Type C and D:
Type C: Nonuniform enhancement (4 patients). Two of the
patients having tumors with this appearance on imaging studies
had gliomas. One of the other patients had a yolk sack tumor and
the other had an unclassified malignant tumor.
Type D: Multcystic lesion with enhancing area (10
patients). Eight of these patients had glimos the others had
malignant teratoma (1 patient) and pineal parenchyma tumor (1
patient).
Types E and F:
Cystic with capsule which may or may not show CT
enhancement and possible MRI enhancement (5 patients). All of
these were pineal glial cysts. Type F: Cyst with no peripheral
enhancement or non-enhancing peripheral tissue. Only one patient
had this configuration-it was an arachnoid cyst.
Surgical Procedures
There were 69 stereo tactic procedures in 37 patients
performed: stereo tactic biopsy was performed in all 37
patients: 19 of these had only a biopsy, 14 others underwent a
stereo tactic third Ventriculostomy at the time of the biopsy to
treat obstructive hydrocephalus and 4 additional patients
underwent aspiration of a at the cyst time of the biopsy. Five
other patients underwent third ventriculostomy as a separate
procedure. All of these patients had first undergone a shunt,
which failed prior to performing third ventriculostomy. Six
additional stereo tactic procedures comprising 6 aspirations of
tumor cysts, 2 installations of P32 and one stereo tactic
placement of an Ommaya reservoir into a tumor cyst were
performed.
Nine of the patients who first underwent a stereo tactic
biopsy later underwent a subsequent craniotomy to resect the
tumor. Sixteen (16)additional patents underwent an open
procedure to resect the lesion(without a stereo tactic biopsy
beforehand).
Mortality and Morbidity
There were no permanent complications in any of the
patients who underwentstereo tactic procedures. One patient had
transient diplopia, which resolved after a few days. Another
patient suffered a non-fatal pulmonary embolis in the
postoperative period. Diagnostic tissue was not obtained in 2 of
the 37 stereo tactic biopsy procedures.
There was one non-fatal postoperative hemorrhage and death
following the 25 open resection procedures (morbilty: 4&,
mortality 4%). One patient, a 73 year old female had a resection
of a pinealoblastoma following unsuccessful radiation therapy.
The surgery was uncomplicated but 12 hours postoperatively she
had a significant hemorrhage into the tumor bed. The
hematoma was evacuated and she made a slow neurologic recovery
with residual midbrain tectal deficits.
A 35-year-old female had undergone empirical radiation
therapy at another institution for a pineal region lesion. The
lesion continued to enlarge in spite of radiation. Upon
presentation at our institution she was found to have a 4.5 cm
diameter tumor, which significantly compressed the midbrain.
Stereotactic biopsy revealed pinealoblastoma and she underwent a
course of chemotherapy, which resulted in a 30% reduction in the
size of the lesion. Resection was then attempted and at an
uncomplicated surgery the lesion was totally removed.
Postoperatively she was neurologically normal but over the next
3 days she developed progressive brainstem dysfunction. CT and
MRI studies showed no hemorrhage but progressive edema of the
brainstem. She died on her 6th postoperative day in spite of
intensive medical therapy.
Discussion
A tissue diagnosis is necessary on all patients with pineal
region tumors who are to undergo radiation therapy, radio
surgery or chemotherapy. In out experience, there is no reliable
means radio logically or by analysis of Oncoproteins in the CSF,
to establish a tissue diagnosis without a surgical procedure.
Tumor histology cannot be inferred from the CT/MRI appearance.
The only lesions, which seem to have distinctive features on
imaging, are lineal glial cysts and arachnoid cysts most of
which do not require surgery anyway. Patient age and sex was
more useful in predicting germ cell histologies than the
determination of Oncoproteins from the CSF, which were positive
in only 1 of 8 germinomas. However, all of the 11 patients
harboring germ cell tumors were male, all were under the age of
25 years. This does not establish that a particular patient has
a germinoma, but does indicate which patients do not have
germinomas.
Progress in microsurgical surgical techniques and advances
in neuroanesthesia have drastically reduced mortality and
morbidity which have been associated with surgical approaches to
lesions in the posterior
third ventricle, transverse cerebral fissure and pineal lesions
in particular. Nonetheless open surgery still has a higher
mortality and morbidity than do stereo tactic biopsy procedures.
Thus there is no reason to subject patients who do not require
tumor resection, I.e. those with germinomas, to the risks of an
open procedure. Stereotactic biopsy can be used to select these
patients for radiation and chemotherapy.
Resection of malignant tumors of the pineal region is a
subject for discussion. As with any surgery, the surgeon must
weigh risk versus benefit of the procedure. It is unlikely that
surgery will cure a malignant glial tumor or malignant pineal
parenchyma tumor. But survival with a malignant tumor or
malignant in this critical region of the CNS will be short
without surgery and the benefit of radiation and chemotherapy
probably less in the face of a significant tumor mass. It is
tempting to establish a tissue diagnosis on patients with
pinealoblastomas by means of a Stereotactic biopsy only and
refer them for radiation therapy or chemotherapy. Unfortunately,
these patients will be back and the surgeon must then face the
unpleasant task patients will be back and the surgeon must then
face the unpleasant task of removing the tumor under more
difficult circumstances: in a surgical field which has to
undergone radiation therapy or in an immunocompromised or
coagulopathic patient following chemotherapy.
Admittedly, the management algorithm described below is
based on a personal philosophy: Germinomas can be managed by
radiation therapy and / or chemotherapy without open surgery.
Pineal parenchyma tumors, teratomas, low-grade glial tumors,
symptomatic vascular lesions, meningiomas and symptomatic pineal
cysts should be resected. Assymptomatic pineal cysts should be
observed with annual imaging studies; most never require
surgery. A tissue diagnosis should be obtained in all patients
who will undergo radiation therapy or chemotherapy.
Therefore, there are only three types of pineal region
lesions: 1) lesions, which are most likely germinomas, 2) those,
which could be germinomas, and 3) those, which are definitely
not germinomas. Germinomas are highly unlikely in females,
patients with cystic lesions and patientsbeyond the age of 30
years of age.
Stereotactic biopsy can be performed to establish the
diagnosis of thegerminoma before referring the patient for
radiation and chemotherapy. In addition, stereo tactic biopsy
can be used to select patients with germinomas from the group of
possible germinomas. The non-germinoma patients in this group
can then undergo an open resection. There is little reason for
performing a stereo tactic biopsy in patients in whom the
presence of a germinomas is extremely unlikely. An open surgical
procedure is recommended.
Bibliography:
1- Abay E.O., Grado G.L., Laws E.R., et al.; Pineal tumors in
children andadolescents. Treatment by CSF shunting and
radiotherapy. J Neurosurg 1981; Vol. 55, pg. 889-895.
2- Apuzzo M.L., Chandrasoma P.T., Zelman V., et al.; Computed
tomographicguidancesterotaxis in the management of lesions of
the third ventricular region. Neurosurgery 1984; Vol. 15, pg.
502-508.
3- Backlund E.O., Rahn T., Sarby B., et al.; Treatment of
pinealobstomas by strategic radiation surgery. Acta Radiol (
Ther) 1974; Vol. 13, pg.368- 376.
4- Conway L. W.: sterotaxis diagnosis and treatment of
intracranial tumors including an initial experience with
cryosurgery for pinealomas. J Neurosurg 1973 Vol. 38. Pg. 453-
460.
5- Dandy W.E.: An operation for the removal of pineal region
tumors. Surg Gynecol Obstet 1921; Vol.33, 113-119.
6- Donat J.F., Gomez M.R., Okasaki H, et al; Pineal tumors; a
53-year experience. Arch Neurol 1978 Vol. 35: pg. 736-740.
7- Edwards M.S., Hudgins R.J., Wilson C.B., et al.: Pineal
region tumors in children. J Neurosurg 1988; Vol.68, pg. 689-
697.
8- Hendrick E.B., Hoffman H.J., Otsubo H., et al.: Intracranial
germ-cell tumors in childrens. J Neurosurg 1991, Vol. 74: pg.
545-551.
9. Kelly P.J.: Tumors Stereotaxis. W.B. Saunders, Philadelphia,
1991.
10. Krause F.: Operative freilegung der vierhugel, mebst
Beobachtungenuber hirndruck and dekompression. Zbl Chir 1926;
Vol. 53, pg. 2812-2819.
11. Lapras C., Patet J.D.: Controversis, techniques and
strategies for pineal tumor surgery. In. Surgery of the third
ventricle. Apuzzo M.L.(ed), William and Wilkins, Baltimore,
1987; Chapter 26, pg. 649-662.
12. Moser.
13. Packer R.J., Sutton L.N., Rosenstock J.G., et al.: Pineal
region tumors of childhood. Pediatric 1984; Vol.
74 pg. 97-102.
14. Pecker J., Scarabin J.M., Vallee B. et al.: Treatment in
tumors of the pineal region: value of sterotactic biopsy. Surg
Neurol 1979; Vol. 12: pg. 341-348.
15. Poppen J., Marino Jr.: Pinealomas and tumors of the
posterior portion of the third ventricles. J Neurosurg 1968;
Vol. 28: pg. 357-364.
16. Sano K., Matsutani M. Pinealoma (germinoma), treated by
direct surgery and postoperative irradiation. A long-term
follow- up. Child’s Brain 1981. Vol. 8: pg. 81-97.
17. Stein B. M.: The infratentorial supracerebellar approach to
pineal lesions. J Neurosurg 1971. Vol. 35: pg. 197-202.
18. Mutsuga N., Sugita K., Takaoka Y., et al. sterotaxis
exploration of para- third ventricle tumors. Confin Neurol 1975;
Vol. 37, pg. 156-162.
19. Van Weganan W.P.: a surgical approach for the removal of
certain pineal tumors- report of a case. Surg Gynec Obest 1931;
Vol. 53, pg.216-220.
Marnie Lucas-Zerbe
Biological Basis of Behavior
Cerebellar Lesions: Neurologist Perspective
March 2005
Cerebellar Lesions and the Neurologist
What is a Neurologist?
A neurologist is a medical doctor trained in the diagnosis
and treatment of nervous system disorders including diseases of
the brain, spinal cord, nerves and muscles
(www.neurologychannel.com). Common nervous system diseases
treated by neurologists include multiple sclerosis, Alzheimer’s
disease, headaches, stroke or injury to the nervous system. The
types of diagnostic tests employed by neurologists to detect
neurological problems include:
• the CAT (computed axial tomography) scan;
• the MRI/MRA (magnetic resonance imaging/magnetic response
angiography);
• lumbar puncture (or spinal tap);
• EEG (electroencephalography);
• and the EMG/NCV (electromyography/nerve conduction
velocity). (www. Neurologychannel.com)
A neurologist can also prescribe medications to treat diseases
or may refer a person to a neurological surgeon if surgical
treatment is needed. (www.my.webmd.com)
Most of their patients are referred to them by other
doctors who suspect their patients problem/s are neurologically
related. Unsure as to exactly what neurological problem their
patients are afflicted with, neurologists act as a kind of
medical detective and work to figure out what the neurological
problem is, what brain structure is implicated in the problem,
where in that brain structure the problem is based, the severity
of the problem, its future implications, and how the problem can
be treated (Phone interview conducted with Licensed Nurse
Practitioner and Neurological Specialist Douglas Lucas 4/05).
This ‘detective work’ is done through a careful screening
process.
A neurological examination includes a series of questions
and tests that provide crucial information about the nervous
system. For the most part, it is an inexpensive, non-invasive
way to determine what might be wrong. The neurological
examination is divided into several components, each focusing on
a different part of the nervous system. These components
include testing patients mental status, cranial nerves, motor
system, sensory system, the deep tendon reflexes, coordination
and the cerebellum, and gait. (www.neurologychannel.com)
Testing for coordination and cerebellum, for example, is
designed to provide clues conditions that affect the cerebellum.
For example, “the neurologist may ask patients to move their
finger from their nose to the neurologist’s finger, going back
and forth from nose to finger, touching the tip of each.
Patients also may be asked to tap their fingers together quickly
in a coordinated fashion or move their hands one on top of the
other, back and forth, as smoothly as they can. Coordination in
the lower limbs can be tested by asking patients to rub one heal
up and down smoothly over the other shin.”
(www.neurologychannel.com)
There is a lot of emphasis placed on getting the diagnosis
exactly right, due to the cost of medical testing. Lucas
stressed that neurologists must work hard to prove to insurance
companies that the tests they prescribe for patients are
relevant and necessary. Insurance approval, he suggested, is
not always easy to attain and restricts the amount and types of
tests that doctors would otherwise like to have preformed. In
the end, Lucas argued, this restrictive use of medical testing
works against the promotion of preventative medicine. Allowing
only those tests that can be directly proven to be linked to
patients symptoms severly limits the ability of doctors to
detect the extent of impairment and to screen for possible
future related impairments (Ibid).
What is the Cerebellum and What Does It Do?
The Cerebellum (or little brain) lies under the cerebrum,
and is composed of two peach-size mounds of folded tissue at the
base of the brain, behind and above the brainstem (www.sfn.org)
The cerebellum is largely involved in coordination. It
coordinates muscle action in both stereotyped movement (e.g.
gait) and in non stereotyped movement (e.g. reaching for
something). The cerebellum contributed to the synergy of muscle
action (synchronization of muscles that act as a group) and
makes sure muscles contract at the right time with the right
force in synchrony with others. The Cerebellum is also involved
with speech allowing for the smooth flow of movement from one
articulatory position to the next. (www.d.umn.edu)
Moreover, a recent functional MRI study suggested that
“motor control is not the cerebellum’s primary function.
Instead scientists found that the cerebellum is most strongly
activated during the acquisition and discrimination of sensor
information suggesting that high cerebellar activity during
motor cognitive activities due to requirement of processing
sensory information. Therefore, while the cerebllar role in
motor control is well known, it someone who’s cerebellum is not
working right may appear clumsy and unsteady. MRI scans are
commonly used and often show shrinkage of part or all of the
cerebellum, although this is not always the case. Blood tests
for specific conditions are now used when a family tendency
toward cereberal dysfunction is detected or suspected. (Hain,
2002)
The main clinical features of cerebellar disorders that
neurologists look for include: incoordination, imbalance, and
troubles with stabilizing eye movements. Cerebellar lesions in
adults have also been shown to produce “impairments in higher
function as exemplified by the cerebellar cognitive affective
syndrome. This syndrome is characterized by deficits in
executive function, spatial cognition, linguistic processing and
affect regulation resulting in overall intellectual impairment.”
(Levisohn, Cronin-Golomb and Schahmann, 2000, pg. 1041) appears
that the cerebellum is involved ia wider range of neural
processing including sensory acquisition and visual function.”
(Nawrot and Rizzo, 1997, p. 2219)
Cerebellum Lesions and What Neurologists Do About Them
The diagnosis of a cerebellar disorder is usually made by
a neurologist and it is generally a strait forward process.
Indeed, because the cerebelleum is heavily involved in
coordination and muscle control,
The two most common distinguishable cerebellar syndromes
are midline and hemispheric. “Midline syndromes are
characterized by imbalance. Persons are usually unsteady on
their feet, they are unable to stand with their eyes open or
closed and are unable to well perform tandem gait (walking).”
(Hain, 2002, www.tchain.com) Persons suffering from severe
midline cerebellar lesions may develop ‘trunkal ataxia’, a
syndrome in which a person is unable to sit on their bed without
steadying themselves. Others may develop ‘titubation’ or a
bobbing motion of the head or trunk. Midline cerebellar
disturbances may also affect eye movements. (Hain, 2002)
The second type of cerebellar syndrome, the hemispheric,
is characterized by incoordination of the limbs. “There may be
decomposition of movement, dysmetra, and rebound.
Dysdiadochokinesis is the irregular performance of rapid
movements. Intention tremors may be present on an attempt to
touch an object. A kinetic tremor may be present in motion and
speech may be dysarthric, scanning, or have irregular emphasis
on syllables.” (Hain, 2002, www.tchain.com) The finger-to-nose
and heel-to-knee tests are the most common tests for a
hemispheric cerebellar dysfunction.
Unfortunately, treatment for cerebellar lesions is
limited. Patients are unlikely to receive only minimal benefit
from medication or therapy. Still, “When specific treatments
are available they are used when the risk of treatment appears
less than leaving the condition alone. Vestibular
rehabilitation treatment may be helpful in that patients can be
made aware of their limits and abilities, and given access to
knowledge concerning walkers, canes and related appliances.”
(Hain, 2002, www.tchain.com) Vestibular rehabilitation is “an
alternative form of treatment involving specific exercises
designed to (1) decrease dizziness; (2) increase balance and
function; (3) increase general activity levels”
(www.vestibular.org). While patients with cerebellar tumors can
sometimes have them removed, most patients continue to have
difficulties in central vestibular processing.
Bibliography
Hain, T.C. (2002.) Cerebellar Disorders. Retrieved from:
http://www.tchain.com/otoneurology/disorders/central/cerebellar.
Levisohn, Lisi, Cronin-Golomb, Alice, and Schmahmann, Jeremy, D.
(2000) “Neuropsychological consequences of cerevellar tumor
resection in children: Cerevellar cognitive affective syndrome
in a paediatric population.” Brain, 123, pp. 1041-1050.
Nawrot, Mark, Rizzo, Matthew. 1997. “Chronic motion perception
deficits from midline cerebellar lesions in human.” Vision
Research 38(1998) pp. 2219-2224.
Neurology Channel. “What is a Neurological Exam?” retrieved
from: http://www.heurologychannel.com/common/PrintPage.php.
Richter, Stefanie, et. all. 2005. “Behavorial and affective
changes in children and adolescents with chronic cerebellar
lesions.” Neuroscience Letters
Elsever Ireland Ltd.
Society for Neuroscience. “What is the Cerebellum?” Retrieved
from:
http://www.sfn.org/content/Publications/BrainBackgrounders/cereb
ellum.htm.
The Motor System. “Neuroanatomy review for motor speech.”
Retrieved from: http://www.d.umn.edu/-
ameredit/Neurogenic%20speech%20disorders/neuroanatomynotes
Vestibular Rehabilitation. “Wat is vestibular rehabilitation?”
retrieved from: http://www.vestibular.org/rehab.html.
Samara Miles-Prystowsky
Biological Basis of Behavior
Cerebellar Lesions: Neuropsychology
March 2005
Cerebellar Lesions:
Neuropsychological Testing, Diagnosis, Treatment
According to an article by Rhawn Joseph, Ph.D., each of the
deep cerebellar nuclei maintains a semi-independent map of the
human body (2000). The cerebellum is tonically active, and is
presumed to exert a stabilizing influence on motor function;
accordingly, it is functionally responsible for coordination and
smooth fine tuning of movement, in addition to influencing
timing. Not only is the cerebellum associated with motor
functioning, but, importantly, also with classical conditioning:
e.g., the learning of new motor programs (Joseph, 2000). It is
associated with the acquisition if finely skilled movements,
such as playing an instrument, playing a sport, and performance
dance. Interestingly, as motor information is acquired, it takes
time for the cerebellum to acquire control over the specific
task. With the notion of “practice makes perfect,” task control
shifts from conscious cortical control (active, practicing
memory) to the subconscious realm and control of the cerebellum.
Hence, the cerebellum plays an integrated and important part in
complex learning and memory (Joseph, 2000.)
During early learning stages, cerebellar climbing fibers
are activated, and mossy fibers seem to modulate and to monitor
ongoing and related activity in the learning context. Lesions
occurring in the cerebellum have the unfortunate effect of
abolishing conditioned response acquisition and retention. Such
lesions and/or diseases cause motor incoordination called
ataxia, with symptoms of tremors, instability and teetering, and
an inability to maintain regular movement of tempo
(nanonline.org).
There are three known major cerebellar syndromes. The
vestibulocerebellar cortex controls movement of the eyes and
body relating to gravity and turning of the head in space;
damage to this area results in ataxia gait and stance, as
described above. The spinocerebellar system, which receives
information via rapid spinocerebellar pathways during the
duration of movement, modulates and smoothes that movement.
Lesions occurring in the spinocerebellar system are a result of
chronic alcoholism and thiamine deficiency (nanonline.org,
Joseph, 2000), and results in difficulty producing rapid and
smooth movements. There occurs a prominent shuffle, wide gait,
and hesitating steps, with ataxia, tremor and difficulty in
lower limb coordination. Lastly, lesions of the
cerebrocerebellum (neocerebellum) have blatant effects on well-
learned volitional movements, as it has direct pathways with
cerebral cortex motor control regions.
Several symptoms exist to suggest cerebellar lesions.
Joseph (2000) reports a study by Gordon Holmes (1971, 1939) that
investigated cerebellar disturbances following gunshot wounds.
Deficits involved voluntary/skilled motor function, gait ataxia,
dysarthria (loss of proprioceptive input), asynergia (loss of
involuntary motor response), hypotonia, and abnormalities in
goal directed voluntary movement (Joseph, 2000; Long,
neuro.psych.memphis.edu). Additionally, visually guided tracking
movements are inhibited. Another symptom, dysmetria, is
indicated by under reaching, over reaching, moving too rapidly
or moving too slowly. As was stated, cerebellar patients
experience hardship in rhythm and timing.
Among the causes of structural cerebellar lesions are
strokes (the most common), multiple sclerosis (often affecting
cerebellar connections in the brainstem and middle cerebellar
peduncle), and tumors. (Hain, 2002.)Three major arteries supply
the cerebellum (Superior Cerebellar Artery, Anterior Inferior
Cerebellar Artery, and Posterior Inferior Cerebellar Artery),
thus heightening the possibility of a stroke causing injury.
Potential stroke syndromes include Wallenberg’s Syndrome/Lateral
Medullary Syndrome, and AIC Artery syndrome.
While a neurologist focuses on physical, empirical
difficulties, looking for abnormalities in physical brain
functioning and testing by way of x-rays, etc., the
neuropsychologist is primarily concerned with behavioral changes
and determining what brain region is injured and what functions
are impaired/remain intact. Therefore, neuropsychologists employ
a variety testing types to inquire about apparent behavior and,
consequently, to conclude as to the type of disorder, the
location, and the type of damage. Neuropsychologists are further
concerned with the cognitive approach, thus focusing on
therapeutic treatment (either in lieu of, following, or in place
of surgery), in addition to diagnosis by observation of physical
and neurological behaviors. (www.neuropsychologycentral.com,
2005).
In the words of the American Academy of Neurology,
“Neuropsychological evaluation can characterize cognitive and
behavioral disturbances and may be helpful to the clinician in
the course of diagnostic assessment, rehabilitation planning, or
development of a management plan” (1996). Effectively, the
neuropsychologist’s evaluation attempts to answer questions such
as, can the person concentrate tasks, for how long, and under
what conditions? How do emotional and/or psychological factors
influence the person’s performance? Physical or neurological
exams, MRIs, and CT scans cannot answer such questions.
(www.neuropsychologycentral.com.) Such examinations should take
place as soon as cerebellar injury is suspected or documented,
and should continue on a frequent, and then gradual, basis,
depending on the functionality of the individual.
When testing, it is important the neuropsychologist should
consider multiple factors, such as the person’s age, education,
ethnicity/cultural influences, and even gender, as each may
influence test results. Other important considerations are
possible substance abuse and/or existing neuropsychiatric
disorders, such as anxiety, psychosis, depression, apathy, and
irritability. Yet perhaps more important than raw data scores
are the particular patterns and strategies patients use to solve
test problems, as they are indicative of neurological activity
and/or problems therein. (Molinari, 1997.) Furthermore, the
neuropsychologist may entail the use of a behavior checklist,
gathering information on touch, hearing, smell, taste, pain,
balance, memory, speech, attention, etc. Cerebellar damage may
result in writing difficulty, irregular gait, and/or
overshooting or undershooting of the limbs. (Schultz, 1999.)
A variety of tests exist for testing cognitive functioning,
several of which were not invented for the purpose of assessing
and diagnosing brain disorders. These more generalized
instruments include the Wechsler Adult Intelligence Scale (WAIS
and WAIS-R) and the Wechsler Memory Scale (WMS and WMS-R). The
WAIS-R is useful in determining disorders that relate to
calculation, visuospatial and attentional capabilities.
Consistency and reliability are quite high for WAIS-R and
acceptable for WMS-R. Another test, the Halstead-Reitan Battery,
was created for the sole purpose of detecting “organic”
dysfunction and to differentiate between those with and without
actual brain damage; however, “differential diagnosis of
neurologic disorders or precise delineation of the underlying
neuronal systems affected was not intended” (AAN, 1996).
Accordingly, most current assessment utilizes a combination of
traditional tests and newer techniques that are specific for
evaluating neurocognitive activities. Notably,
neuropsychological assessment is not specifically intended to
diagnose or indicate precise location of focal brain lesions,
but, rather, is useful in indicating a lesion as the cause of
correlating expressed symptoms (American Academy of Neurology,
1996).
In a study by Molinari et al., patients were tested in a
serial reaction-time task, and “learning was manifested by the
reduction in response latency over the sequential blocks”
(Molinari, 1997). The study found that reaction times by
patients with lesions were longer when stimuli were presented in
sequence. Patients were significantly impaired in both detection
and repetition. However, when sequences were learned before
testing, motor performance increased. Thus, according to this
study, cerebellar lesions specifically induce impairment in
procedural learning of motor sequences. (Molinari et al., 1997).
Aside from testing for neurocognition, neuropsychologists
can also test for physical coordination abilities. For example,
persons with midline cerebellar syndrome have difficulty with
balance. They are unsteady, may exhibit “trunkal ataxia” (an
inability to sit on a bed without steadying themselves) or
“titubation” (bobbing motion of head or trunk). Those with
hemispheric cerebellar syndromes have incoordination in the
limbs, as shown by dysmetria, dysdiadochokinesis (the “irregular
performance of rapid altering movements”), and decomposition of
movement. Intention tremors may occur when the person tries to
touch an object, and kinetic tremors may occur in motion
activities. Two classic tests for hemispheric cerebellar
dysfunction are the finger-to-nose and heel-to-knee tests. One
study focused on investigating the affect of focal cerebellar
lesions on procedural learning. Again, while these tests are
useful in determining probable causes of symptoms, a neurologist
is more likely to make a specific diagnosis and determine lesion
location through MRI scanning and other related methods. (Hain,
2002.) The neuropsychologist should thus conclude by initiating
behavioral and cognitive therapy, not only to assist the patient
in handling the emotional and psychological stresses of
cerebellar injury, but also to attempt recovery of “normal”
behavioral functioning.
References
American Academy of Neurology (1996). Assessment:
Neuropsychological testing of adults. Neurology; 47:592-599.
Hain, T.C. (2002.) Cerebellar Disorders. Retrieved on March
25, 2005 from:
http://www.tchain.com/otoneurology/disorders/central/cerebellar.
Joseph, R. (2000.) The Cerebellum. Neuropsychiatry,
Neuropsychology, Clinical Neuroscience; Academic Press, New
York. Retrieved from: http://brainmind.com/cerebellum.html.
Lalonde, R. and Botez-Marquard, T. (2000).
Neuropsychological deficits of patients with chronic or acute
cerebellar lesions. Journal of Neurolinguistics, 13, 117-128.
Long, C.J. Neuropsychology/Behavioral Neuroscience:
Cerebellum. Retrieved on March 23, 2005 from:
http://neuro.psyc.memphis.edu/NeuroPsyc/np-ugp-cerebell.htm
Molinari, M. et al. (1997.) Cerebellum and procedural
learning: evidence from focal cerebellar lesions. Brain, 120,
10; Oxford University Press.
National Academy of Neuropsychology (1997). Neurological
Disorders: Cerebellar Lesions and Syndromes. Retrieved on March
23, 2005 from:
http://nanonline.org/nandistance/mtbi/NeuroIll/movement/cerebel.
html.
Neuropsychology Central. Evaluation of Traumatic Brain
Injury. Retrieved on March 25, 2005 from:
http://www.neuropsychologycentral.com/interface/content/resource
s/resources_interface_frameset.html.
Schulz, G.M. and Dingwall, W.O. (1999). Speech and oral
motor learning in individuals with cerebellar atropy. Journal of
Speech, Language and Hearing Research, 42, 1157-1176.
Wickelgren, I. (1998). The cerebellum: The brain's engine of
agility. Science, 281, 1588-1591.
Nicolette Schlick
Bio Basis of Psychology
Patient perspective
March 2005
Cerebellar Lesions: Patient Him/Herself
The cerebellum integrates sensory and other inputs to
coordinate ongoing movements and participate in motor planning.
The cerebellum has no direct connections to the lower motor
neurons but modulates motor function through upper motor
neurons. The Vermis and flocculonodular lobes regulate balance
and eye movements via connections with vestibular nuclei and
oculomotor system, these regions control the medial motor
systems. The more lateral areas of the cerebellum control
muscles of extremities, the most lateral areas control function
in motor planning. (Chapter 15 Cerebellum)
When cerebellar lesions occur they produce ataxia
(irregular uncoordinated movement.) Ataxia occurs ipsilateral to
the side of the cerebellar injury. Midline cerebellar lesions
cause unsteady gate (truncal ataxia) and eye movement
abnormalities (nystagymas), which are often accompanied by
vertigo, nausea and vomiting. Lateral cerebellar lesions cause
limb ataxia. (Chapter 15 Cerebellum)
Patients with cerebellar damage, regardless of the cause or
location, exhibit persistent errors in movement. These movement
errors are always on the same side of the body as the damage to
the cerebellum, reflecting the cerebellum's unusual status as a
brain structure in which sensory and motor information is
represented ipsilateral rather than contra laterally.
Furthermore, somatic, visual, and other inputs are represented
topographically within the cerebellum; as a result, the movement
deficits may be quite specific. For example, one of the most
common cerebellar syndromes is caused by degeneration in the
anterior portion of the cerebellar cortex in patients with a
long history of alcohol abuse. Such damage specifically affects
movement in the lower limbs, which are represented in the
anterior spinocerebellum. The consequences include a wide and
staggering gait, with little impairment of arm or hand
movements. Thus, the topographical organization of the
cerebellum allows cerebellar damage to disrupt the coordination
of movements performed by some muscle groups but not others.
The implication of these pathologies is that the cerebellum
is normally capable of integrating the moment-to-moment actions
of muscles and joints throughout the body to ensure the smooth
execution of a full range of motor behaviors. Thus, cerebellar
lesions lead first and foremost to a lack of coordination of
ongoing movements. For example, damage to the
vestibulocerebellum impairs the ability to stand upright and
maintain the direction of gaze. The eyes have difficulty
maintaining fixation; they drift from the target and then jump
back with a corrective saccade, a phenomenon called nystagmus.
Disruption of the pathways to the vestibular nuclei may also
result in a loss of muscle tone. (Nanonline.org)
In contrast, patients with damage to the spinocerebellum; a
lesion that usually occurs in patients with alcoholism and
thiamine deficiency, have difficulty controlling walking
movements; they have a wide-based gait with small shuffling
movements, which represents the inappropriate operation of
groups of muscles that normally rely on sensory feedback to
produce smooth, concerted actions. The patients also have
difficulty performing rapid alternating movements such as the
heel-to-shin and/or finger-to-nose tests, a sign referred to as
dysdiadochokinesia. Over- and under reaching may also occur
(called dystamia). During the movement, tremors called action or
intention tremors accompany over, and undershooting of the
movement due to disruption of the mechanism for detecting and
correcting movement errors.
Finally, lesions of the cerebrocerebellum have a direct
connection with the motor control areas of the cerebral cortex.
They produce impairments in highly skilled sequences of learned
movements, such as playing a musical instrument. It has also
been implicated that the memory for such movements can be
disrupted.(Nanonline.org)
Cerebellar lesions also occur in patients who have had a
stroke. In one case study a 51-year-old patient who suffered a
stroke had laughter or crying attacks immediately after his
stroke. He also revealed gaze- evoked nystagmus with rightward
gaze and right rotary nystagmus of both eyes at rest. After
coordination examination the patient showed ataxia with right
finger-to-nose and heel-to-shin tests. His motor strength and
reflexes were normal as well as all sensory abilities.
(brain.oupjournals.org)
The pathological laughter and crying attacks were sudden
and were of moderate intensity. He was embarrassed by the
attacks and could only moderately control the attacks. The
patient was also observed that PLC (Pathological Laughter and
Crying) was similar with the triggering stimulus, for instance
the patient would cry at a joke and laugh in response to a
frustrating test failure. Except for his outbursts the patient’s
personal and social behavior was entirely appropriate. However
he noted that in spite of the lack of an appropriate laughter-
or crying- inducing stimulus he would eventually feel jolly or
sad after a long episode of laughter and crying. A feeling was
being produced, consistent with the emotional expression and in
the absence of an appropriate stimulus for that emotional
expression. (brain.oupjournals.org)
The patient was also observed that there were “priming”
effects in determining whether he would laugh or cry in response
to a given stimulus. If he had laughed recently he was more
likely to laugh in response to the next effective stimulus,
independent of its actual emotional value. And if he had
recently laughed or cried the threshold for responding with
laughter or crying was lowered for subsequent stimuli. Because
of these effects there would be long periods of time up to 30
minutes or more during which he would repeatedly laugh or cry to
a neutral stimuli. As a treatment for this patient’s PLC, he was
given a SSRI citalopram 20mg/day. (brain.oupjournals.org)
In another case study a 53-year-old male had a lesion
removed from his right cerebellar cortex. He has a slight ataxia
and intention tremor in his right arm. He developed compensatory
strategies, which allow him to continue his hobby of drawing. He
his right handed and uses his predominate and slightly ataxic
arm to draw. He has difficulty drawing a straight line and
lettering. Indicating a high level of visual-motor coordination
and motor skills are preserved in the arm ipsilateral to the
cerebellar pathology. He did not have any clinical evidence of
auditory deficits. His voluntary eye blink control and
trigeminal blinking were within normal limits. (Bracha, V.,
Zhoa, L., Wunderlich, D.A., Morrissy, S.J., Bloedel, J.R.,
(1997)
A 49 year-old male had a large lesion in the right
cerebellum involving the cerebellar hemispheric cortex, parts of
the Vermis and the cerebellar nuclei. He displayed dysarthia, a
strong cerebellar ataxia of the right arm and leg, and a
significant intention tremor (a tremor that is present only when
the person is moving the limb), which interferes with any
writing or fine movements. He has impaired balance and uses a
cane to stabilize himself. After surgery, he had a slight
diplopia related to the residual palsy of the right superior
oblique muscle. (Bracha, V., Zhoa, L., Wunderlich, D.A.,
Morrissy, S.J., Bloedel, J.R., (1997) The common denominator of
all of these signs, regardless of the site of the lesion, is the
inability to perform smooth, directed movements.
References
1. Pathological Laughter and Crying, Brain a Journal of
Neurology,
http://brain.oupjournals.org/cgi/content/full/124/9/1708
acquired from the internet on 4-2-05
2. Patients with cerebellar lesions cannot acquire but are
able to retain conditioned eyeblink reflexes, Bracha, V., Zhoa,
L., Wunderlich, D.A., Morrissy, S.J., Bloedel, J.R., (1997)
Oxford University Press
3. Neurological Disorders, Movement Disorders, Cerebellar
Lesions and Syndromes,
http://nanonline.org/nandistance/mtbi/NeuroIll/movement/cerebel.
html, acquired from the internet on 4-2-05
4. Neuroscience Consequences of Cerebellum Lesions, Purves,
D., Fitzpatrick, D., Augustine, G.J., Katz, L.C.,(2001) Sinauer
Associates Inc.
5. Chapter 15 Cerebellum,
http://web.odu.edu/webbroot/intr/sci/Kcarson.nsf/files/chapter15
.ppt/$FILE/chapter15.ppt. Acquired from the internet on 4-2-05.
Kellie Corbisiero
Bio Basis of Psychology
Perspective of the Spouse
March 2005
From the Perspective of the Spouse
The cerebellum is the main part of the brain where primary
motor functions take place, so lesions in this area of the brain
are extremely serious. It is located at the bottom rear of the
head just above the brainstem (see picture 1). Although the
cerebellum looks small it contains nearly 50% of all of the
neurons in the brain, and the cerebellum handles nearly 200
million inputs. The cerebellum is involved in computing
movements, the measurement of time, directing attention and many
other motor and cognitive functions. The cerebellum is an
essential part of the brain and a lesion to the brain can cause
severe problems (wikipedia.org).
I have recently noticed my husband eliciting odd behavior,
he recently has had difficulty moving, he seams to have a
hesitation or a slight tremor before attempting to make a
movement. A good example was when my husband began to walk over
to the bathroom he hesitated and had difficulty reaching for the
bathroom door. I also noticed another odd behavior of my husband
elicited when he began to reach for his coffee cup and he used
an excessive amount of force and instead of grabbing his coffee
cup he knocked it clear across the room. After noticing this odd
behavior, I took my husband to see a doctor who referred us to a
neurologist, who informed us of a lesion that had occurred in my
husbands cerebellum(wikipedia.org).
The cerebellum is key in motor coordination and lesions to
the cerebellum cause difficulty in performing such tasks. An
issue that the spouse needs to realize is that their partner may
have language problems, which may cause them to become
frustrated when attempting to say a particular sentence it takes
them several attempts, so you need to be patient. Some people
with these lesions only have poor verbal intelligence and
problems with complex language tasks. While some other patients
also exhibit auditory comprehension problems, such as difficulty
reading and writing. Another issue that concerns cerebral
lesions can be problems associated with the storage of
information, which is another issue the spouse needs to be
concerned with because they may need to verbally remind their
significant other several times about simply tasks (Schmidt).
Another common symptom of a cerebral lesion is ataxia which
is a type of motor coordination difficulty. Another issue that
the spouse needs to be concerned with is that the patient may
have slight tremors of the affected limbs which are only present
when the person is moving that particular limb. These types of
tremors are called intentional tremors. When walking from heel-
to-toe, which is called tandem gait, the effected person may
teeter back and forth. Movements such as finger-to-nose and heel
to knee to shin movements there are large side to side
alterations when the patient begins to approach a target. When
the patient attempts to do rapid movements such as tapping the
forefinger with the thumb, the patients cannot maintain a
regular movement or tempo, so again patients is needed when
dealing with individuals with cerebral lesions. Overall the
spouse of an individual with cerebral lesions needs to elicit
patients and help the individual, to help improve their lives as
much as possible (Movement Disorders)
Co-worker/Employers
A important issue that the co-workers and the employers
need to deal with when having an employee/co-worker with a
cerebral lesion is if they can still continue to do their job
efficiently. An example of a professional with a cerebral lesion
was a lawyer. This lawyer had various language disturbances had
problems storing information, and would often not be able to
associate clients names to their particular case. This lawyer
also had difficulties with verb generation and other word
generations tasks. In this particular case the lawyer was no
longer able to work because he now lacked the abilities to
perform well in the work place. In this particular case the
employer would need to remove such person from the work place,
or possibly assign them to smaller tasks that they could
complete with their cerebral lesion disabilities (Schmidt).
When working with people who have sustained cerebral lesions,
the employers need to make crucial decisions and properly
understand the issue at hand to decide the best way to treat
their employee. Generally people who have sustained cerebral
lesions have difficulty speaking properly, so if the job
requires a lot of verbal communication the employee would not do
well and their difficulty of speaking could possibly confuse
customers causing frustration. Another issue is that the
employee may have a difficult time comprehending tasks that were
assigned by the employer, which may cause frustration on the
part of the employer and employee. Despite these verbal and
comprehension problems, the individuals IQ is not any lower, and
the employer could possibly work out a particular job for the
individual that requires little comprehension and verbal
communication, but such jobs are difficult to find. Employees
with cerebral lesions if ever hired are usually placed in low
positions with low opportunities to advance (Fabbro, 2000).
Fabbro,F., Moretti, R., Bava, A. (2000). Language impairments in
patients with cerebellar lesions. Journal of Neurolinguistics,
13 (2-3), 173-188.
Movement Disorders. Retrieved April 9, 2005, from
http://nanonline.org/nandistance/mtbi/NeuroIll/movement/cerebel.
html
Schmidt, G.L. Language and the Cerebellum. Retrieved April 10,
2005, from
http://lamar.colostate.edu/~gschmidt/cerebellum.htm#_Lesion_Evid
ence_for
Wikipedia Encyclopedia. (2005, April 14). Retrieved April 14,
2005, from http://en.wikipedia.org/wiki/Cerebellum
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This page last edited 1-3, 2005
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