John Waterston

Sensory neuropathy as part of the cerebellar ataxia neuropathy vestibular areflexia syndrome

Objective: The syndrome of cerebellar ataxia with bilateral vestibulopathy was delineated in 2004. Sensory neuropathy was mentioned in 3 of the 4 patients described. We aimed to characterize and estimate the frequency of neuropathy in this condition, and determine its typical MRI features. Methods: Retrospective review of 18 subjects (including 4 from the original description) who met the criteria for bilateral vestibulopathy with cerebellar ataxia. Results: The reported age at onset range was 39–71 years, and symptom duration was 3–38 years. The syndrome was identified in one sibling pair, suggesting that this may be a late-onset recessive disorder, although the other 16 cases were apparently sporadic. All 18 had sensory neuropathy with absent sensory nerve action potentials, although this was not apparent clinically in 2, and the presence of neuropathy was not a selection criterion. In 5, the loss of pinprick sensation was virtually global, mimicking a neuronopathy. However, findings in the other 11 with clinically manifest neuropathy suggested a length-dependent neuropathy. MRI scans showed cerebellar atrophy in 16, involving anterior and dorsal vermis, and hemispheric crus I, while 2 were normal. The inferior vermis and brainstem were spared. Conclusions: Sensory neuropathy is an integral component of this syndrome. It may result in severe sensory loss, which contributes significantly to the disability. The MRI changes are nonspecific, but, coupled with loss of sensory nerve action potentials, may aid diagnosis. We propose a new name for the condition: cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome (CANVAS).

Cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS): a review of the clinical features and video-oculographic diagnosis

The association of bilateral vestibulopathy with cerebellar ataxia was first reported in 1991 and delineated as a distinct syndrome with a characteristic and measurable clinical sign—an absent visually enhanced vestibulo‐ocular reflex—in 2004. We reviewed 27 patients with this syndrome and show that a non‐length‐dependent sensory deficit with absent sensory nerve action potentials is an integral component of this syndrome, which we now call “cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome” (CANVAS). All patients had brain MRI and 22/27 had evidence of cerebellar atrophy involving anterior and dorsal vermis, as well as the hemispheric crus I. Brain and temporal bone pathology in one patient showed marked loss of Purkinje cells and of vestibular, trigeminal, and facial ganglion cells, but not of spiral ganglion cells. There are two sets of sibling pairs, suggesting CANVAS is a late‐onset recessive disorder. The characteristic clinical sign—the visual vestibulo‐ocular reflex deficit—can be demonstrated and measured clinically using video‐oculography.

Chronic migrainous vertigo

A series of 16 subjects is described who presented with chronic vertigo that was thought to be migrainous in nature. The vertigo occurred on a daily basis and had been present for six months or more. Common symptoms included motion-induced dizziness, positional vertigo and motion sensitivity. Investigations were frequently normal apart from the finding of atypical positional nystagmus in four subjects and unilateral vestibular hypofunction in two subjects. It was frequently not possible to make a diagnosis of migraine on the basis of International Headache Society criteria, however the dramatic beneficial response to anti-migraine therapy supported the hypothesis that the vertigo was migrainous in nature.

Feasibility of percutaneous transluminal angioplasty for carotid artery stenosis.

Percutaneous transluminal balloon angioplasty was attempted in seven patients with internal carotid artery stenosis, including one patient who had two procedures. All had recurrent, carotid territory, neurological symptoms considered haemodynamic in origin. Six had occlusion of the contralateral internal carotid artery. Cerebral blood flow studies confirmed diminished cerebrovascular reserve in six patients studied. In five patients (six procedures) angioplasty of the stenosed internal carotid artery was carried out successfully. With two patients technical difficulty in crossing the stenosis prevented angioplasty and in one patient with bilateral stenosis the procedure was not attempted on the second side because of the severity of the stenosis. In two patients transient aphasia developed during cannulation of the carotid artery and in another a transient monoparesis developed during the procedure. Both these haemodynamic complications recovered within ten minutes. No other complications occurred. Our experience suggests that balloon angioplasty is technically feasible in the management of stenotic carotid disease associated with haemodynamic stroke. It is a technically simple procedure requiring only a brief admission to hospital. However, its general application to patients with thromboembolic carotid-territory stroke will depend on the risk/benefit ratio compared to carotid endarterectomy or to conventional medical treatment.

A pilot study of falls risk and vestibular dysfunction in older fallers presenting to hospital Emergency Departments

Purpose. To compare falls risk in older fallers and non-fallers, with an emphasis on dizziness and signs of vestibular dysfunction. Method. The fallers had presented to the Emergency Department of the Royal Melbourne Hospital, Australia following a fall and were discharged directly home (n = 20) (75% female, mean age 78 years). The non-fallers were an age and gender matched group, who had not fallen in the past 12 months (n = 20). All clients received a home-based assessment, which involved a comprehensive assessment of falls risk. Results. Over three-quarters of the fallers took four or more medications, had balance impairments, and used a gait aid in the community. The fallers had a significantly higher falls risk score (P < 0.001), demonstrated significantly poorer balance (P < 0.001) and walked significantly more slowly (P < 0.001) than the non-fallers. There was no significant difference between the groups in their reports of dizziness (P = 0.68), although static balance testing (CTSIB condition 5) suggested a greater degree of underlying vestibular dysfunction in the group of fallers (P < 0.001). Conclusion. Older people discharged home from the ED following a fall are at high risk of falling in the future and have a greater level of vestibular dysfunction based on simple clinical testing. Additional clinically applicable tests of vestibular function are required to further investigate the relationship between vestibular dysfunction and falling in older people.

[Vestibular migraine: diagnostic criteria: consensus document of the Bárány Society and the International Headache Society].

This paper presents diagnostic criteria for vestibular migraine, jointly formulated by the Committee for Classification of Vestibular Disorders of the Bárány Society and the Migraine Classification Subcommittee of the International Headache Society (IHS). The classification includes vestibular migraine and probable vestibular migraine. Vestibular migraine will appear in an appendix of the third edition of the International Classification of Headache Disorders (ICHD) as a first step for new entities, in accordance with the usual IHS procedures. Probable vestibular migraine may be included in a later version of the ICHD, when further evidence has been accumulated. The diagnosis of vestibular migraine is based on recurrent vestibular symptoms, a history of migraine, a temporal association between vestibular symptoms and migraine symptoms and exclusion of other causes of vestibular symptoms. Symptoms that qualify for a diagnosis of vestibular migraine include various types of vertigo as well as head motion-induced dizziness with nausea. Symptoms must be of moderate or severe intensity. Duration of acute episodes is limited to a window of between 5 minutes and 72 hours.

The Influence of Otolith Dysfunction on the Clinical Presentation of People With a Peripheral Vestibular Disorder

Background and Purpose Traditional vestibular function testing has measured horizontal semicircular canal function only. Otolith function tests have recently been developed, but their clinical significance has not been determined. The purpose of this study was to investigate the influence of otolith dysfunction on the clinical presentation of individuals with a peripheral vestibular disorder. Subjects and Methods Twenty-one subjects with loss of horizontal semicircular canal function only and 37 subjects with combined loss of horizontal semicircular canal and otolith organ function were recruited. All subjects received a comprehensive clinical assessment, including self-report questionnaires and measures of balance performance. Results No significant differences were identified between subjects with or without otolith dysfunction with respect to symptom severity, self-perceived handicap, functional limitations, or balance performance. Discussion and Conclusion Otolith dysfunction does not significantly influence the clinical presentation of individuals with a peripheral vestibular disorder. Other factors, including symptom severity, may be more influential.

Vestibuläre Migräne: diagnostische Kriterien

This paper presents diagnostic criteria for vestibular migraine, jointly formulated by the Committee for Classification of Vestibular Disorders of the Bárány Society and the Migraine Classification Subcommittee of the International Headache Society (IHS). The classification includes vestibular migraine and probable vestibular migraine. Vestibular migraine will appear in an appendix of the third edition of the International Classification of Headache Disorders (ICHD) as a first step for new entities, in accordance with the usual IHS procedures. Probable vestibular migraine may be included in a later version of the ICHD, when further evidence has been accumulated. The diagnosis of vestibular migraine is based on recurrent vestibular symptoms, a history of migraine, a temporal association between vestibular symptoms and migraine symptoms and exclusion of other causes of vestibular symptoms. Symptoms that qualify for a diagnosis of vestibular migraine include various types of vertigo as well as head motion-induced dizziness with nausea. Symptoms must be of moderate or severe intensity. Duration of acute episodes is limited to a window of between 5 minutes and 72 hours.

Unilateral vestibulotoxicity due to systemic gentamicin therapy

Systemic gentamicin can cause acute bilateral, simultaneous, symmetrical loss of vestibular function manifested by symptoms and signs of chronic vestibular insufficiency (ataxia and oscillopsia). We report 6 patients presenting with ataxia and oscillopsia, but without a history of vertigo, who had severe unilateral loss of vestibular function on caloric testing. The absence of vertigo in these patients could be explained by two possible mechanisms: either, the unilateral loss of vestibular function was subacute, occurring over several days so that compensation could occur, or bilateral vestibular loss occurred which was then followed by asymmetrical recovery of vestibular function. The second hypothesis is supported by the observation that vestibular hair cells can regenerate after aminoglycoside damage.

Coordination of eye and head movements during smooth pursuit in patients with vestibular failure.

During pursuit of smoothly moving targets with combined eye and head movements in normal subjects, accurate gaze control depends on successful interaction of the vestibular and head movement signals with the ocular pursuit mechanisms. To investigate compensation for loss of the vestibulo-ocular reflex during head-free pursuit in labyrinthine-deficient patients, pursuit performance was assessed and compared under head-fixed and head-free conditions in five patients with isolated bilateral loss of vestibular function. Target motion consisted of predictable and unpredictable pseudo-random waveforms containing the sum of three or four sinusoids. Comparison of slow-phase gaze velocity gains under head-free and head-fixed conditions revealed no significant differences during pursuit of any of the three pseudo-random waveforms. The finding of significant compensatory eye movement during active head movements in darkness in labyrinthine-deficient patients, which were comparable in character and gain to the vestibular eye movement elicited in normal subjects, probably explains the similarity of the head-fixed and head-free responses. In two additional patients with cerebellar degeneration and vestibular failure, no compensatory eye movement response was observed, implying that the cerebellum is necessary for the generation of such responses in labyrinthine-deficient patients.