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Friedreich's ataxia: electrophysiological and histological findings
Author(s) -
Caruso Giuseppe,
Santoro Lucio,
Perretti Anna,
Serlenga Luigi,
Crisci Claudio,
Ragno Michele,
Barbieri Fabrizio,
Filla Alessandro
Publication year - 1983
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1111/j.1600-0404.1983.tb04542.x
Subject(s) - electrophysiology , sural nerve , ataxia , nerve conduction velocity , electromyography , medicine , tibial nerve , abnormality , rheobase , anatomy , sensory nerve , sensory system , motor nerve , neuroscience , biology , physical medicine and rehabilitation , stimulation , psychiatry
‐ Electromyography was performed, and motor and sensory nerve conduction velocities were measured in 19 patients definitely affected by Friedreich's ataxia. Biopsy of the sural nerve was also performed in 9 patients. Most patients presented a moderate to severe loss of motor units, a significant increase in mean duration of motor unit potentials, and in the incidence of polyphasic potentials. Short‐lasting spontaneous activity was rarely seen. Conduction velocity along the motor and sensory fibres of the median and tibial nerves was moderately slowed, while distal conduction time to muscle was significantly increased and the sensory orthodromicallyevoked response markedly reduced. Intraoperative electrophysiological recordings obtained during biopsy of the sural nerve in 4 patients were consistent with the changes conventionally observed in the median, tibial and sural (6 patients) nerves. Quantitative histology revealed a reduced number of total myelinated fibres with a severe loss of large fibres, and a moderate loss of fibres of less than 7 μm in diameter. In teased nerve fibre preparations, the most evident abnormality consisted of fibres with uniformly short internodal length, while signs of remyelination were less prominent. Signs of active axonal degeneration were rarely observed in electron microscopy. Electrophysiological and histological findings were uniformly distributed, and the changes were neither related to the duration nor to the severity of the clinical condition.