The epidemiology of intermittent and chronic ataxia in children in Manitoba, Canada

Abstract

Aim To determine the epidemiology of chronic ataxia in children in Manitoba, Canada. Method A retrospective study using multiple sources and disease codes identified children (age 0–16y) with chronic ataxia (>2mo duration or recurrent episodes of ataxia) seen at Winnipeg Children's Hospital from 1991 to 2008. Patients with isolated peripheral nerve diseases, vestibular disorders, or brain tumors were excluded. Results We identified 184 patients (males=females; mean age 15y, SD 7y 8mo) with chronic ataxia. Median age at the presenting symptom onset was 1 year 3 months and at ataxia onset 3 years 1 month. Median duration of follow‐up was 6 years 5 months. During the study period, the crude incidence rate was 5.77 in 10 000; the crude prevalence rate was 6.59 in 10 000; and the crude mortality rate 0.446 in 10 000. The most common presenting symptoms were developmental delay, ataxia, or seizures. The most common diagnoses (known in 129) were Angelman syndrome (n=16), ataxia telangiectasia (n=13), mitochondrial disease (n=9), Friedreich ataxia (n=7), stroke (n=7), and familial/genetic episodic ataxia (n=7). Interpretation Chronic ataxia is a relatively common early‐presenting symptom in childhood. A specific diagnosis is possible in 70% of patients after extensive investigations. The mortality rate is relatively low and the disease burden is high with significant comorbidities including developmental delay and epilepsy.

Neuro-Ophthalmological Findings in Children and Adolescents with Chronic Ataxia

“…However, our detailed and multiple search strategies likely minimised this potential problem. 1 Our investigation is based on a hospital sample and assessments by multiple specialists, which may bias our findings. As in all retrospective studies, some information was missing, inaccurate, poorly or inadequately documented (e.g., type of nystagmus), or incomplete.…”

“…Further demographic details have already been published on this cohort. 1 The aetiology of chronic ataxia was known in 128 patients. One hundred and fifteen of 184 patients had 214 N-OS (median = 2, range: 1-5 N-OS per patient).…”

“…Methodological details have already been described. 1 Ethical approval for the study was granted by the Research Ethics Board of the University of Manitoba. Relevant information was collected from the patients' hospital medical charts, including age, gender, aetiology, and N-OS, as follows: decreased visual acuity (best corrected is less than 20/40 from any cause including amblyopia and cortical visual impairment); abnormal visual fields on clinical examination or perimetry; abnormal pupillary examination including abnormal pupillary size, reaction to light or accommodation, or relative afferent pupillary light defect; abnormal optic discs on funduscopy, e.g., pallor; impaired ductions (i.e., eye movements checked in each eye alone) caused by III, IV, or VI cranial nerve palsy; saccadic dysmetria; saccadic (jerky) smooth ocular pursuit; pathological nystagmus; and ocular misalignment, e.g., strabismus.…”

“…The annual crude incidence of chronic ataxia is 3.2 per 100,000 children and adolescents less than 17 years old. 1 Ataxia is caused by a multitude of disorders. 2 The clinical features, their evolution, and a detailed family history may point to the diagnosis.…”

“…In prior studies of a large cohort of children with chronic ataxia, we reported on the epidemiology and ethnic distribution of the various aetiologies encountered. 1,5 In this study, our aims were to describe the N-OS and their frequencies in general and by disease aetiology more specifically in paediatric patients with chronic ataxia in Manitoba, Canada. We hypothesised that neuro-ophthalmological features occur commonly in diseases that cause paediatric chronic ataxia and they vary with disease aetiology.…”