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Clarifying variability of corticomotoneuronal function in kennedy disease
Author(s) -
Vucic Steve,
Kiernan Matthew C.
Publication year - 2011
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.22017
Subject(s) - transcranial magnetic stimulation , silent period , motor neuron , subclinical infection , neuroscience , stimulation , motor cortex , evoked potential , medicine , psychology , spinal cord
Although Kennedy disease (KD) is regarded as a pure lower motor neuron disorder, recent transcranial magnetic stimulation (TMS) studies have reported subclinical corticomotoneuronal dysfunction in KD. To clarify these findings, this study applied novel triple stimulation (TST) and threshold tracking TMS techniques to gain further insights into corticomotoneuronal function in KD. Methods: TMS studies were undertaken in 12 KD patients and 38 age‐matched controls. Motor evoked potentials were recorded over the abductor pollicis brevis (threshold tracking TMS) and abductor digiti minimi (TST). Results: The mean TSTtest:TSTcontrol amplitude (99 ± 0.7%, normal >93%) and area (98.4 ± 1.6%, normal >92%) ratios were normal in Kennedy disease. In addition, short‐interval intracortical inhibition (SICI) was similar in KD and controls (KD: 8.1 ± 1.3%; controls: 10.1 ± 0.7%; P = 0.11), as were the motor evoked potential amplitude, resting motor threshold, intracortical facilitation, and cortical silent period duration. Conclusions: Triple stimulation and threshold tracking TMS techniques have reiterated normal corticomotoneuronal function in KD. Muscle Nerve, 2011