Sporadic adult onset ataxia of unknown etiology
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- Abele, M., Minnerop, M., Urbach, H. et al. J Neurol (2007) 254: 1384. doi:10.1007/s00415-007-0556-1
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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).
To define and characterize the clinical phenotype of sporadic adult onset ataxia of unknown etiology (SAOA).
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.
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).
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.
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.