Altered sensorimotor integration in Parkinson’s disease

• Published in: Brain (London, England : 1878) Vol. 125; no. 9; pp. 2089 - 2099
• Main Authors: Lewis, Gwyn N., Byblow, Winston D.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.09.2002; Oxford Publishing Limited (England)
• Subjects: Aged; Aged, 80 and over; Arm - physiopathology; Biological and medical sciences; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; ECR = extensor carpi radialis; Electric Stimulation; Electromyography; Evoked Potentials, Motor; FCR = flexor carpi radialis; Female; Humans; Ia afferent; ICI = intracortical inhibition; intracortical inhibition; ISI = interstimulus interval; Magnetics; Male; Medical sciences; MEP = motor evoked potential; Middle Aged; Motion; Motor Cortex - physiopathology; Movement; Muscle, Skeletal - physiopathology; Neural Inhibition; Neurology; Parkinson Disease - physiopathology; Parkinson's disease; r.m.s. = root mean square; Reference Values; RTh = rest threshold; Sensation; sensorimotor integration; TES = transcranial electrical stimulation; TMS = transcranial magnetic stimulation; transcranial magnetic stimulation; Human; Nervous system diseases; Parkinson disease; Exploration; Stimulation; Cerebral disorder; Transcranial route; Electrodiagnosis; Sensorimotor coordination; Magnetic; Central nervous system disease; Degenerative disease; Electromyography; Upper limb; Extrapyramidal syndrome
• ISSN: 0006-8950; 1460-2156; 1460-2156
• DOI: 10.1093/brain/awf200

Transcranial magnetic stimulation (TMS) was used to investigate sensorimotor integration in the upper limb of 10 patients with Parkinson’s disease and 10 age‐matched controls. Non‐conditioned and subthreshold conditioned (2 ms interstimulus interval) responses were recorded in the flexor and extensor carpi radialis muscles (FCR and ECR) of the more impaired (non‐dominant) limb. Stimuli were delivered while the wrist joint was positioned statically at various joint angles as well as during different phases of passive movement of the wrist joint (90° amplitude, 0.2 Hz). The FCR and ECR muscles remained relaxed during all stimulation. In both groups, responses in the static condition were larger when the target muscle was in a shortened position. Responses were also facilitated in the muscle shortening phases of passive movement. In both static and dynamic conditions, the extent of modulations in response amplitude was significantly reduced in the patient group. The level of intracortical inhibition (ICI) was also significantly less in the Parkinson’s disease patients in static conditions. During passive movement, control subjects demonstrated a clear reduction in ICI compared with the static trials; however, the level of ICI was unchanged in the Parkinson’s disease group in the dynamic condition. The results suggest an abnormal influence of afference on corticomotor excitability in Parkinson’s disease. This may be related to abnormal sensory input, a defective integrative unit or an inappropriate motor response.