Ataxia

Clinic

• Lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements.
• Ataxia can be limited to one side of the body, which is referred to as hemiataxia.
• Dystaxia is a mild degree of ataxia.

Cerebellar ataxia

Dysfunction of the cerebrocerebellum (Lateral hemispheres) Appendicular ataxia	Intention tremor Coarse trembling Accentuated over the execution of voluntary movements Possibly involving head, eyes, limbs and torso	Peculiar writing abnormalities Large, unequal letters Irregular underlining	Peculiar Dysarthria Slurred speech characterized by explosive variations in voice intensity despite a regular rhythm	Dysdiadochokinesia Inability to perform rapidly alternating movements which could involve rapidly switching from pronation to supination of the forearm. Movements become more irregular with increases of speed.	Dysmetria Hypometria or overshooting Hypermetria Inability to judge distances or ranges of movement happens.	Rebound phenomenon Loss of the check reflex	Schmahmann's syndrome Patients may exhibit a constellation of subtle to overt cognitive symptoms
Dysfunction of the spinocerebellum (Vermis and areas near the midline)	Truncal ataxia: Uncertain starts and stops Lateral deviations Unequal steps
Vestibulocerebellum dysfunction Flocculonodular lobe	Balance disturbances Control of eye movements Postural instability Negative Romberg's test

Cerebellar ataxia Black-Box

Entities Miasms	Hyper Rreflexia	Hypo Reflexia	Dysarthria	Nystagmus
GSS	+++	+++	+++	+++
CJD	+++		+++	+++
HSV-1		+++
KRU			+++

Sensory Ataxia

Clinic

• Sensory Ataxia is a form of ataxia caused not by cerebellar dysfunction
• It is due to
  • Loss of Sensory input / Proprioception (Positions of joint and body parts)
  • Dysfunction of dorsal columns of spinal cord (Because they carry proprioceptive information up to brain)
  • Dysfunction of the various parts of the brain that receive positional information, including the cerebellum, thalamus, and parietal lobes.

Vestibular Ataxia

• It is used to indicate ataxia due to dysfunction of the vestibular system
• Acute and unilateral cases is associated with prominent vertigo, nausea, and vomiting.
• In slow-onset, chronic bilateral cases of vestibular dysfunction, these characteristic manifestations may be absent, and dysequilibrium may be the sole presentation.

Bilateral vestibular hypofunction Spinocerebellar ataxia

Vestibulocerebellar ataxia

Truncal or trunk ataxia

• Truncal ataxia is caused by midline damage to the cerebellar vermis
• It is a wide-based "drunken sailor" gait characterized by uncertain starts and stops, lateral deviations and unequal steps.
• It is an instability of the trunk and often seen during sitting.
• It is most visible when shifting position or walking heel-to-toe.
• As a result of this gait impairment, falling is a concern in patients with ataxia.
• Truncal ataxia affects the muscles closer to the body such as the trunk, shoulder girdle and hip girdle. It is involved in gait stability.

Truncal ataxia causes

Common	Uncommon
Alcohol intoxication Cerebral infarction Cerebral hemorrhage Cerebellar ataxia Multiple sclerosis Friedreich's ataxia Drugs such as Benzodiazepines, Lithium, Phenytoin	Adrenoleukodystrophy Ataxia oculomotor apraxia type 1 Branchial myoclonus Christianson syndrome Dandy–Walker syndrome Dysequilibrium syndrome Epilepsy Episodic ataxia Post viral cerebellar ataxia	GSS Machado–Joseph disease Microcephaly N-acetylaspartate deficiency Neuhauser–Eichner–Opitz syndrome Paraneoplastic cerebellar degeneration Polymicrogyria Rett syndrome Spinocerebellar ataxia Vertebral dissection