Sporadic adult onset ataxia of unknown etiology : A clinical, electrophysiological and imaging study

Research Area: Research Year: 2007
Type of Publication: Article
Authors: Abele, M; Minnerop, M; Urbach, H; Specht, Karsten; Klockgether, T
BACKGROUND: The sporadic adult onset ataxias of unknown etiology (SAOA) denote the non-hereditary degenerative adult onset ataxias that are distinct from multiple system atrophy (MSA). OBJECTIVE: To define and characterize the clinical phenotype of sporadic adult onset ataxia of unknown etiology (SAOA). DESIGN: A survey of clinical features, nerve conduction and evoked potentials, autonomic tests, and magnetic resonance imaging (MRI)-based brain morphometry was conducted in patients with SAOA. PATIENTS: Study subjects were a consecutive sample of 27 patients (11 male, 16 female) who met the diagnostic criteria for SAOA (age 55 +/- 13 years; age at disease onset 47 +/- 14 years; disease duration 8 +/- 7 years). RESULTS: All patients presented with a cerebellar syndrome. The most frequent extracerebellar symptoms were decreased vibration sense in 70% and decreased or absent ankle reflexes in 33% of the patients. Nerve conduction studies revealed a polyneuropathy in 26% of the patients. Somatosensory evoked potentials were abnormal in 44%, and central motor conduction time in 17% of patients. Autonomic testing revealed an affected autonomic nervous system in 58% of patients. Voxel-based brain morphometry showed a predominant reduction of gray matter in the cerebellum which was significantly correlated with disease stages. A loss of white matter was found in both middle cerebellar peduncles and the outer edge of the pons. CONCLUSIONS: The data show that SAOA is a predominantly, but not exclusively cerebellar disorder. Clinical, electrophysiological, and imaging findings showed some similarities with multiple system atrophy which raises the question of an overlap of these two disorders.
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