Vestibulocerebellar ataxia

Clinic

• Also known as Vestibulocerebellar syndrome is a progressive neurological disorder
• Initially symptoms present as periodic attacks of abnormal eye movements but may intensify to longer-lasting motor incapacity.
• The disorder has been localized to the vestibulocerebellum, specifically the flocculonodular lobe.

Sign / Symptoms

• Gaze-paretic nystagmus is one of the most common symptoms among patients results in poor gaze-holding due to neuron integrator dysfunction.
• Rebound nystagmus is also frequently found in conjunction with gaze-paretic nystagmus and is characteristic of cerebellar malfunction.
• Poor or absent smooth pursuit (ability of the eyes to follow a moving object)
• Strabismus (misalignment of the eyes)
• Diplopia
• Oscillopsia (the sensation that stationary objects in the visual field are oscillating)
• Abnormal vestibulo-ocular reflex (reflex eye adjustment to stabilize gaze during head movement).

• Ataxia (loss of voluntary muscle coordination)
• Tinnitus

Vertigo

• Periodic attacks of vertigo, tinnitus, and ataxia that are associated with sudden changes in head position.
• Attacks were seen to vary in duration from a few minutes to months in different individuals and were often accompanied by nausea and vomiting.
• During a typical attack, patients reported having ataxic gait with a tendency to fall to either side while lacking the ability to walk heel-to-toe.
• With more severe attacks, patients had to sit down due to extreme unsteadiness.
• Fine motor abilities, such as writing and buttoning clothes, became impaired during an attack.
• However, speech remained unaffected.
• Attacks did not cause a loss of consciousness nor did they disturb mental activity.
• Once the attack ended, oscillopsia faded and the intensity of nystagmus decreased.
• Although these attacks are similar to episodic ataxia, patients with vestibulocerebellar syndrome do not completely lose motor control in arms and legs or experience dysarthria (poor speech articulation), as patients with episodic ataxia do.
• The disturbances to vestibular function during periodic attacks are the primary distinction between vestibulocerebellar syndrome and other similar neurological syndromes.
• These conditions do not consistently cause the symptoms of dizziness and ocular impairment that have been localized to the vestibulocerebellum, leading researchers to characterize vestibulocerebellar syndrome as a distinct disorder.

Entities

• Nystagmus
• Ataxia
• Diplopia
• Vertigo
• Hearing impaire

Miasms

• STLE
• VZV

Note

• This is Vestibulocerebellar ataxia, so I could consider Cerebellar Ataxia, as an appropriate entity. By this rubric, VZV and STLE catch same rate.
• But here we have Tinitus, that dose not a special rubric. But If I consider Hearing, Impaired, VZV is top

Causes

• Vestibulocerebellar syndrome is caused by a failure in the function of the flocculus of the vestibulocerebellum, one of the three main divisions of the cerebellum.
• Generally, the cerebellum is responsible for regulating motor commands. The main function of the vestibulocerebellum is to receive sensory input from the vestibular nuclei in the brainstem and to regulate equilibrium, balance, and the vestibulo-ocular reflex accordingly. The vestibulo-ocular reflex, one of the primary areas affected by vestibulocerebellar syndrome, is responsible for counterrotating the eyes in response to head movements. This allows gaze to stay fixed on a specific point. A failure in this reflex results in a variety of eye movement abnormalities, such as those exhibited in vestibulocerebellar syndrome.

Vestibulocerebellar syndrome has been categorized as an autosomal dominant neurological disorder although the specific effect on the vestibulocerebellum is unknown. It is possible that inheritance causes abnormalities in either the flocculus or in structures that project into the flocculus to maintain stability of the retinal image of stationary or moving visual objects. Pathological symptoms of the disorder may appear within the first 1–2 years of life although time of onset varies greatly among patients. The severity of symptoms typically progresses with age. The exact cause of the disorder and its pathogenic effect on the flocculus is unknown. A single genetic locus, however, critical in early eye movement control pathways on chromosome 13q31-q33 has been discovered. This locus may be involved in some of the ocular abnormalities that occur in affected individuals. Chromosome 13q31-q33, however, has not been seen to correspond to any known existing gene or locus responsible for congenital nystagmus, one of the primary symptoms of vestibulocerebellar syndrome, or for better-understood cerebellar ataxias.

Vestibulocerebellar syndrome shares clinical similarities with autosomal dominant ataxias, particularly episodic ataxia types 1 and 2. These similarities include gaze-evoked and rebound nystagmus and vertigo. Furthermore, the symptoms appear to progress over time. The molecular basis of many of these other disorders has been thoroughly established and in some cases a genetic locus has been identified. Despite the similarities between symptoms of episodic ataxia and vestibulocerebellar syndrome, studies of affected individuals have shown that the disorder is genetically distinct from these other similar neurological conditions. To date, the molecular basis of vestibulocerebellar syndrome remains undefined.

DD

Vestibular Neuritis