cerebellar disorder

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Cerebellum and Vestibular system
5TH
stage of students at Ibn sina college of Medicine
By
Lecturer Dr. Mahmood Abdul Munem
Neurologist at Ibn Sina university.
M.B.CH.B/F.I.C.M

3. Objectives:
At the end of this lecture the students will be able to:
Understand the basic knowledge for Cerebellum and Vestibular system
Recognise the Signs and symptoms of Cerebellar and Vestibular dysfunction
Identify causes of Cerebellar and Vestibular diseases.

4. Content
Cerebellum Anatomy
Cerebellar function
Causes of Cerebellar diseases
Vestibular system anatomy
Symptoms and signs of Vestibular system disorders
Most common disease of vestibular system

5. Cerebellum

6. The Cerebellum Anatomy
cerebellum is divided into three major lobes by
transverse fissures:
The flocculonodular lobe(vestibulocerebellum)
The anterior lobe.
The posterior lobe.
more functionally useful method of describing
the cerebellum is based on its longitudinal zone
patterns and their different connections into:
Vermis
Hemisphers

7. Connection to Brain

8. Activity ‫رقم‬ ‫نشاط‬
1
Why cerebellar lesion affect the same side of the body?

10. Function
The cerebellum, principally a motor organ, is responsible for:
1. The regulation and control of muscular tone
2. The control of gait
3. The coordination of movement by synergistic action, especially voluntary movement. Its main role
is to orchestrate the force, rate, sequence and timing of muscular contraction required to produce
steady volitional movement that are generated in the cerebral hemispheres.
4. Maintains equilibrium. Equilibrium is the ability to maintain the orientation of the body and its
parts in relation to the external space. The flocculonodular lobe receives special proprioceptive
impulses from the vestibular nuclei.
5. The processes of procedural (skill) learning reside primarily in the motor system, and specifically in
the cerebellum.

11. Defective muscular control resulting in irregular and clumsiness of movement
that is not the result of muscular weakness. Ataxia can affect eye movement,
speech, limbs, trunk, stance (the standing posture) and gait.
There are three types of ataxia:
Cerebellar ataxia
Vestibular ataxia
Sensory ataxia
Cerebellar ataxia divided into two types: truncal ataxia due to disequilibrium
and limb ataxia due to incoordination
Ataxia

12. Signs of cerebellar ataxia
A) Specific cerebellar signs (signs of incoordination): disturbance in force, rate, sequence, direction, or
timing of movement. (Hemispheric lesion)
1- Intention tremor: as approaches the target, oscillation appears because the irregularities in rate and force
of movements pronounced during termination of movement.
2- Dyssynergia: Dyssynergestic movements ( fragmentations)
3- Dysdiadochokinesia: clumsiness in performing alternating movement.
4- Dysmetria (past pointing): irregular errors in the distance and force of limb movements.
5- Impairment of the check reflex (impaired rebound): impairment of the ability to check the force of
muscular contraction.

13. B) Nonspecific cerebellar signs:
1- Hypotonia. Hypotonia accompanies acute cerebellar hemispheric lesions and is seen less often with
chronic lesions.
2- Scanning and staccato dysartheria.
3- Ocular movement: Ocular movements may be impaired as a result of cerebellar disease.
Nystagmus.
Gaze impairment: Patients with cerebellar lesions are unable to hold lateral positions of gaze.
4- Ataxic gait Symptomatic cerebellar lesions universally impair the gait and stance (the standing
posture).
Vermis lesion : gait ataxia and truncal ataxia due to disequilibrium.(Wide base gait)
hemispheres lesion : the gait is drunken like gait with veering to one side in unilateral lesion and to both
sides in bilateral cerebellar lesion.
5- Pendular reflexes

14. Signs of cerebellar Lesion
Midline cerebellar lesion Hemisphere lesion
Broad base gait. Hypotonia.
Vertical nystagmus Nystagmus.
Head and trunk titubation Drunken like gait
Dysartheria (left paravermal lesion).
Incoordination signs

15. Causes of cerebellar ataxia
A. Sudden: Vascular (cerebellar infarction or hemorrhage)
B. Acute and Subacute
1. Infection: cerebellitis
2. Metabolic: drugs (Carbamazepine), Wernicke's encephalopathy
3. Inflammatory and autoimmune disease
C. Chronic
1- Acquired deficit: 2- Hereditary
Drugs: phenytoin posterior fossa malformations
Alcoholic cerebellar degeneration Wilson’s disease
MS ataxia-telangiectasia
Tumors, paraneoplastic. hypothyroidism hereditary spinocerebellar ataxias(FA)
Gluten ataxia

17. Friedreich ataxia is progressive cerebellar ataxia and accounts for approximately one half
of all cases of hereditary ataxia.
Friedreich ataxia is an autosomal recessive spinocerebellar disorder, which has a slow but
relentlessly degenerative course.
The current hypothesis is that frataxin is a mitochondrial protein and a defect in its action
may result in abnormal accumulation of iron in mitochondria, leading to excess production
of free radicals, which then results in cellular damage and death. (long tracts of the dorsal
columns, pyramidal system, and peripheral nerves).
Prevalence is 1-2 per 100,000. Men and women are affected equally.
Women have a significantly better prognosis than men.
Friedreich ataxia

18. Clinical manifestations
usually begin at aged 8-15 years.
Ataxia of gait is the most frequent presenting symptom.
The hands usually become clumsy months or years after the gait disorder, and dysarthric
speech appears after the arms are involved.
pes cavus and kyphoscoliosis precede the neurologic symptoms. In others, these follow
by several years.
Deep tendon reflexes are absent.
Plantar responses are extensor.
Distal wasting.
Impaired vibration and proprioception sense.
Diabetes mellitus occurs in 10% of patients with Friedreich ataxia.
Heart disease is present in at least two thirds of patients with Friedreich.
Significant sensorineural deafness occurs in 10% of persons with Friedreich ataxia.

19. Diagnosis
Confirmation of the diagnosis by DNA testing is recommended for all patients
in whom Friedreich ataxia is clinically suspected.
MRI findings are normal or show mild cerebellar atrophy (usually observed
late in the disease). The cervical spinal cord often is atrophied.
Echocardiogram exhibits evidence of hypertrophic cardiomyopathy in
approximately 40% of patients.
Electrocardiogram is abnormal in approximately two-thirds of patients.

20. Treatment /Mortality/Morbidity
Medical Care: No treatment to date has been shown to delay, stop, or reverse the progression of Friedreich
ataxia is known. Diabetes must be managed. Cardiac failure and arrhythmias should be treated as they arise.
Surgical Care: Surgery for foot deformity and scoliosis may be of benefit in selected patients.
The rate of progression is variable, but more than 95% of individuals with Friedreich ataxia cannot ambulate
by the time they are aged 45 years, and, on average, patients lose the ability to walk 15 years following onset
of symptoms.
The mean age of loss of ambulation is 25 years. Age at death is rather variable. Death usually occurs in the
mid fourth decade of life. Death tends to be earlier if heart disease and diabetes are associated.

21. Vestibular disorder
Vertigo is the typical symptom caused by vestibular dysfunction.
most patients with vertigo have :
1. acute vestibular failure
2. benign paroxysmal positional vertigo
3. Ménière's disease.
4. Central (brain) causes of vertigo are rare by comparison, with the exception of
migraine.

23. Acute vestibular failure
commonly called ‘labyrinthitis’ or ‘vestibular neuronitis’,
most cases are idiopathic or viral.
It usually presents as isolated severe vertigo with vomiting and unsteadiness.
It begins abruptly, often on waking, and many patients are initially bed-bound.
The vertigo settles within a few days, though head movement may continue to provoke
transient symptoms (positional vertigo) for some time.
During the acute attack, nystagmus will be present for a few days.
Cinnarizine, prochlorperazine or betahistine provide symptomatic relief but should not be
used long term, as this may delay recovery.
A small proportion of patients fail to recover fully and complain of ongoing imbalance and
dysequilibrium rather than vertigo; vestibular rehabilitation by a physiotherapist may help.

24. Benign paroxysmal positional vertigo
Due to the presence of otolithic debris from the saccule or utricle affecting the
free flow of endolymph in the semicircular canals (cupulolithiasis).
-transient (seconds) vertigo precipitated by movement (typically, rolling over in
bed or getting into or out of bed).
Dx by Hallpike maneuver
self-limiting after weeks or months.
Tx Epley Maneuver

25. Ménière disease
This is due to an abnormality of the endolymph that causes episodes of vertigo
accompanied by tinnitus and fullness in the ear, each attack typically lasting a
few hours.
Over the years, patients may develop progressive deafness (typically low-tone on
audiometry). Examination is typically normal in between attacks.
Dx is clinical, supported by abnormal audiometry. Imaging may be indicated to
exclude other focal brainstem or cerebellopontine angle pathology but will be
normal in Ménière disease.
Management includes a low-salt diet, vestibular sedatives for acute attacks (e.g.
cinnarizine or prochlorperazine), and occasionally surgery to increase
endolymphatic drainage from the vestibular system.

26. References
1- Davidson’s principles and practice of medicine.
2- CONTINUUM: Lifelong Learning in Neurology