Evaluation of ataxia

Ataxia is a neurologic syndrome characterized by clumsy and uncoordinated movement of the limbs, trunk, and cranial muscles. It results from pathology in the cerebellum and its connections, or in the proprioceptive sensory pathways. The list of causes of ataxia is extensive. Typically, when considering a differential diagnosis, ataxia is classified on the basis of whether it is acute, subacute, or chronic. Ataxia may also be classified by age of onset (childhood vs. adult), whether it is hereditary or acquired, and whether it is associated with other clinical features (e.g., seizures, dystonia, vision loss). Degenerative ataxia is the term used to denote ataxia related to cerebellar atrophy of both genetic and unknown causation. Other terms that have been used for this type of ataxia in a broad sense include spinocerebellar degenerations and olivopontocerebellar atrophy, but these are becoming obsolete. National Ataxia Foundation external link opens in a new window

Epidemiology

There are no precise data regarding the prevalence of ataxia of all causes.[1]Polo JM, Calleja J, Combarros O, et al. Hereditary ataxias and paraplegias in Cantabria, Spain. An epidemiological and clinical study. Brain. 1991 Apr;114 (Pt 2):855-66. http://www.ncbi.nlm.nih.gov/pubmed/2043954?tool=bestpractice.com [2]Leone M, Bottachi E, D'Alessandro G, et al. Hereditary ataxias and paraplegias in Valle d'Aosta, Italy: a study of prevalence and disability. Acta Neurol Scand. 1995 Mar;91(3):183-7. http://www.ncbi.nlm.nih.gov/pubmed/7793232?tool=bestpractice.com Epidemiologic studies that focus on hereditary types of ataxia have shown a prevalence of around 10 per 100,000 population, and idiopathic ataxia probably outnumbers hereditary cases.[3]Muzaimi MB, Thomas J, Palmer-Smith S, et al. Population based study of late onset cerebellar ataxia in south east Wales. J. Neurol Neurosurg Psychiatry. 2004 Aug;75(8):1129-34. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1739172/pdf/v075p01129.pdf http://www.ncbi.nlm.nih.gov/pubmed/15258214?tool=bestpractice.com Since there are many causes of degenerative and inherited ataxias, each individual type of ataxia is relatively rare. In the case of genetic forms of ataxia, there are clusters of high incidence of specific types due to founder effects and ethnic and geographic variations in the prevalence of many mutations.[4]Schöls L, Bauer P, Schmidt T, et al. Autosomal dominant cerebellar ataxias: clinical features, genetics, and pathogenesis. Lancet Neurol. 2004 May;3(5):291-304. http://www.ncbi.nlm.nih.gov/pubmed/15099544?tool=bestpractice.com