Correlation of Clinical Neuromusculoskeletal and CentralSomatosensory Performance: Variability in Controls and PatientsWith Severe and Mild Focal Hand Dystonia

[摘要] Focal hand dystonia (FHd) is a recalcitrant,disabling movement disorder, characterized byinvoluntary co-contractions of agonists andantagonists, that can develop in patients whooveruse or misuse their hands. The aim of thisstudy was to document clinical neuromusculoskeletalperformance and somatosensoryresponses (magnetoencephalography) in healthycontrols and in FHd subjects withmildversusseverehand dystonia. The performance ofhealthy subjects (n = 17) was significantly betterthan that of FHd subjects (n = 17) on all clinicalparameters. Those withmild dystonia(n = 10)demonstrated better musculoskeletal skills,task-specific motor performance, and sensorydiscrimination, but the performance of sensoryand fine motor tasks was slower than that ofpatients withsevere dystonia. In terms ofsomatosensory evoked field responses (SEFs),FHd subjects demonstrated a significantdifference in the location of the handrepresentation on the x and y axes, loweramplitude of SEFs integrated across latency,and a higher ratio of mean SEF amplitude tolatency than the controls. Bilaterally,. those withFHd (mildandsevere) lacked progressivesequencing of the digits from inferior tosuperior. On the affected digits, subjects withsevere dystoniahad a significantly higher ratioof SEF amplitude to latency and a significantlysmaller mean volume of the cortical handrepresentation than those withmild dystonia.Severity of dystonia positively correlated withthe ratio of SEF mean amplitude to latency(0.9029 affected, 0.8477 unaffected; p<0.01).The results of the present study strengthen theevidence that patients with FHd demonstratesigns of somatosensory degradation of the handthat correlates with clinical sensorimotordysfunction, with characteristics of the dedifferentiationvarying by the severity of handdystonia. If these findings represent aberrantlearning, then effective rehabilitation mustincorporate the principles of neuroplasticity.Training must be individualized to each patientto rebalance the sensorimotor feedback loopand to restore normal fine motor control.

[学科分类] 精神健康和精神病学