F response abnormality in Parkinson's disease.
The F response was recorded from the 1st dorsal interosseous muscle (1st DI) and two antagonistic muscles, the flexor digitorum brevis (FDB) and the extensor digitorum brevis (EDB), in 16 patients with Parkinson's disease and 22 age-matched normal controls. In Parkinson's disease, the F responses from the 1st DI and the FDB occurred more frequently with a longer duration and a greater number of phases in comparison with the normal controls. In addition, the coefficient of variation of onset latency was significantly smaller in Parkinson's disease. On the other hand, the F response recorded from the EDB showed the same tendency as that from the FDB, but not to a significant extent. These findings suggest that the excitability of the spinal motor neurons is enhanced in rigid parkinsonian patients. It thus seems reasonable to assume that the main underlying cause of rigidity is an excessive supraspinal drive to the spinal motor neurons, including an increase in motoneuron excitability.
Naito
Y
Y
Department of Neurology, Institute of Clinical Medicine, University of Tsukuba, Japan.
Komatsu
Y
Y
Kanazawa
I
I
Nakanishi
T
T
D000870:Anterior Horn Cells / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology*; D009127:Muscle Rigidity / Q000503:physiopathology; D009132:Muscles / Q000294:innervation*; D010300:Parkinson Disease / Q000503:physiopathology*; D010525:Peripheral Nerves / Q000503:physiopathology; D011930:Reaction Time / Q000502:physiology; D012815:Signal Processing, Computer-Assisted