Ataxia

Neurological symptoms

MOVEMENT DISORDERS • • • • •

Tremors rhythmic oscillating movement of extremities or head Types: Action Tremors- essential, familial, senile type tremors of posture or activity, disappearing with rest, usually assymetrical, head are commonly involved but legs are rarely affected, lower amplitude than parkinsonism • NO rigidity or bradykinesia, maybe relieved temporarily with alcohol intake • Neurological exam ___/Normal • DDx: pheochromocytoma (increase catecholamines) hyperthyroidism, toxins, amphetamines, lithium, amytriptyline intake

• Resting tremor- Parkinsonism • Gross: 3-7/ sec “pill rolling” resting tremor that improves with movement • higher age group, not relieved by alcohol • PE: decreased facial expression, rigidity of the limbs, shuffling gait, slow movement, patient is depressed, may lead to dementia • Intention tremor • - due to cerebellar dysfunction

• Tardive dyskinesia • - usually due to prolonged intake of neuroleptics • Manifestations: oral-buccal-lingual dyskinesia ( e.g tongue protrusion, lip smacking, facial grimacing) , may involve limbs and trunks as well • Hemiballismus • Wild involuntary flinging of an extremity due to CVD (Cerebrovascular) of subthalamic nuclei • Acute dystonic posture (e.g. turning of neck) • Usually caused by neuroleptic idiosyncrasy • Myoclonus • Shock-like non-patterned contraction of a muscle, entire muscle or group of muscle secondary to anoxic brain damage, epilepsy, degenerative disease

WRITER’S CRAMP(A type of FOCAL DYSTONIA) Patients describe a discomfort in the hand associated with use of excessive force. Abnormal posturing is typical.

Example of patient’s script in writer’s cramp.

POST ANOXIC DYSTONIA. Foot posture.

POST ANOXIC DYSTONIA. Secondary callous.

TARDIVE DYSKINESIA. Various form of spontaneous tongue move ment.

MS. Facial myokymia in its most extensive form causing narrowing of the palpebral conjunctiva and slight elevation of the angle of the mouth. Facial myokymia consist of fine unilateral flickering movement of the muscle that maybe confined to one area of the face or maybe present throughout the facial nerve distribution.

BLEPHAROSPASM.This disease produces excessive blinking to the point where the eye becomes permanently closed

OCCULOGYRIC CRISIS

SPASMODIC TORTICOLIS. A characteristic head posture. Contraction of the left sternomastoid is particularly prominent.

ATAXIA • Disorder of coordination and rhythm • • • • • • • • • • • •

Locate the lesion Frontal lobe lesion Tumors (meningioma, glioma, metastatic tumor) Sign of cerebellar dse (fronto-ponto-cerebellar pathways Staggering gait, alternating pronation supination test (APST), nystagmus (tends to fall backwards[frontal lesion]) Perseveration, grasp & suck reflex, incontinence & slowness of mentation Headache is common, dementia maybe present Anterior cerebral artery syndrome -also affects frontal lobe -aneurysm of ant communicating artery may affect frontal lobe Hydrocephalus -enlarged frontal horns of lateral ventricle affects leg fibers and may produce ataxia (plus me

• Subcortical Lesions • Mechanism: involvement of corticocerebellar connections and pyramidal tract dysfunction • Multiple strokes (‘etat lacunaire) • -ataxia, emotional labilities, brisk reflexes (increased jaw jerk), dysarthria, dementia

• Brainstem Lesions • Mechanism: involvement of cerebellar tracts • Most common cause of ataxia secondary to brainstem lesions: CVA, multiple sclerosis • Brainstem signs • -crossed motor & sensory findings • -internuclear ophthalmoplegia • -nystagmus • -dysarthria

• Cerebellar Lesion • Mechanism: direct involvement of coordination pathways • Signs: limb, trunk, gait & speech ataxia, nystagmus, hypotonia • Causes : • Cerebellar haemorrhage, infarct, tumor • -occipital headache and ocular gaze palsies • -Normal limb strength and sensation • -tumors seen in children, rare in adults • -metastatic tumors in adult • Spinocerebellar degeneration • -the syndrome include olivo-ponto-cerebellar degeneration & Friedrich’s ataxia

• -(+) family history and widespread nervous system involvement (e.g. peripheral neuropathy, upgoing toes, etc) • Alcoholism or occult malignancy • -associated with cerebellar degeneration • -alcoholic degeneration (ataxia of gait and of legs, less prominent involvement of arms, speech and ocular motility, associated with polyneuropathy) • -Wernicke’s encephalopathy (acute ataxia and oculomotor paralysis associated with alcoholism, responds well to thiamine)

• Spinal Cord Lesion • • • • • • • • • • • • • • •

Mechanism: ataxia via the posterior column dysfunction, involvement of spinocerebellar tracts or spasticity from involvement of pyramidal tracts) (+) Romberg’s test - indicates posterior column disease Cervical spondylosis with associated cervical myelopathy -(+) neck and arm pain -there maybe posterior column dysfunction and upgoing toes (pyramidal tract involvement) Multiple Sclerosis -often involves spinal cord -other CNS lesion + (+) history of previous attacks Vitamin B12 deficiency -combined system disease (e.g. involvement of posterior and lateral columns of spinal cord -general weakness and paresthesias which lead to leg stiffness & ataxia -loss of position and vibration sense associated with upgoing toes + decreased or absent knee and ankle jerks secondary to peripheral neuropathy -see mental changes Other causes of ataxia secondary to spinal cord dysfunction Spinal cord tumor, spinocerebellar degeneration, syringomyelia, tabes dorsalis, amyotrophic lateral sclerosis

• Peripheral Nerve Lesion • -ataxia secondary to weakness and in idiopathic polyneuritis due to dorsal root involvement • Idiopathic polyneuritis (Guillain-Barre Syndrome) • -may present as ataxia in early stage • Dx: absent reflex, increased CSF protein, slow nerve conduction time • Muscular Lesion • Ataxia secondary to muscular weakness • Myopathy - acquired: polymyositis, thyroid myopathy • Congenital: muscular dystrophy (Duchene’s) • Acute forms: drug or chemical ingestion (alcohol, lead), acute labyrinthitis, postictal states (after seizures), LE

AGNOSIA • Object recognition • AGNOSIA – defect of recognition of simple objects in the presence of adequate primary sensory perception • visual agnosia – failure of visual recognition of an object, due to a lesion in the visual association area (area adjacent to the calcarine occipital cortex), – visuospatial agnosia – if he cannot revisualize familiar places such as his home and cannot maintain orientation in a previously known environment. – finger agnosia – inability to identify own fingers (due to a lesion of the angular gyrus and frequently forms a part of GERTSMANN’s syndrome – finger Agnosia, Allochiria (right-left disorientation), Agraphia and Acalculia.

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tactile agnosia (astereognosis) – inability to recognize objects by palpatation, due to a lesion of the posterior parietal lobe. –

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autotopagnosia – loss of appreciation or identification of a body part in which the patient may fail to identify his own limb or even one side of the body, it is a lesion of the parietal lobe, demonstrated by willingness of the patient to accept the examiner’s hand or arm as his own. anosognosia – implies denial of disease due to loss of perception of the affected part, usually a paralyzed limb, due to a frontal & parietal lobe lesion of the non-dominant hemisphere.

auditory agnosia – inability to perceive the meaning of sound despite the absence of deafness.

APRAXIA • Praxis – inability to execute a planned motor action, in the absence of paralysis. • There are three stages considered in the development of a skilled act: the development of an idea of movement, formulation of the plan of its execution, and finally, motor performance of the plan (basis of the three types of apraxia)

• Ideational apraxia – due to lesion in the supramarginal gyrus of the parietal lobe, no impairment of motor mov’t but idea is confused, ex. Request px. To light cigarette, px. Fails to take cigarette out of the package. • Ideamotor apraxia – occurs when there is interface with the transmission of the appropriate impulses transcortically to the motor centers to convert the idea into coordinated motor action, seen in diffused cortical disease ex. Patient is unable to carry out the desired action like lick protrude the tongue upon request.

• Motor apraxia – failure to perform a series of finer skilled movements on request in the absence of weakness or paralysis, planned mov’t involving limbs as a whole is intact, lesion is in the pre-motor frontal cortex on the opposite side to the affected limb, there is loss of dexterity in handling small objects or performing rapid finger movements.

DRESSING APRAXIA. Typically associated with lesion of the non dominant parietal lobe.

END OF LECTURE