Alterations in spike amplitude distribution of the surface electromyogram post-stroke

We examined surface electromyogram (EMG) characteristics during voluntary isometric activation of the first dorsal interosseous (FDI) muscle in stroke survivors. Five stroke subjects participated in the study. They were instructed to generate isometric contraction at different force levels. The recording was performed in both paretic and contralateral muscles using a matched force protocol. Comparisons of the spike amplitude distribution of the surface EMG signals were made between paretic and contralateral muscles. For a given contraction level, a widened or narrowed spike amplitude distribution was observed in paretic muscles of stroke subjects. Such differences may be induced by degeneration of some spinal motoneurons and/or disorganization of motor unit control properties after stroke.

[1]  W Z Rymer,et al.  Abnormal force--EMG relations in paretic limbs of hemiparetic human subjects. , 1981, Journal of neurology, neurosurgery, and psychiatry.

[2]  A Cruz Martinez,et al.  Electromyography, single fibre electromyography and necropsy findings in myasthenic syndrome associated with bronchogenic carcinoma. , 1982, Electromyography and clinical neurophysiology.

[3]  C. D. De Luca,et al.  Relationship between firing rate and recruitment threshold of motoneurons in voluntary isometric contractions. , 2010, Journal of neurophysiology.

[4]  P Girlanda,et al.  Muscle rearrangement in patients with hemiparesis after stroke: an electrophysiological and morphological study. , 1993, European neurology.

[5]  Naoichi Chino,et al.  The physiological functional loss of single thenar motor units in the stroke patients: when does it occur? Does it progress? , 2004, Clinical Neurophysiology.

[6]  W F Brown,et al.  Denervation in hemiplegic muscles. , 1990, Stroke.

[7]  S. Beniczky,et al.  Large motor units are selectively affected following a stroke , 2008, Clinical Neurophysiology.

[8]  G Kamen,et al.  Superficial motor units are larger than deeper motor units in human vastus lateralis muscle , 2005, Muscle & nerve.

[9]  Chein-wei Chang,et al.  Evident trans-synaptic degeneration of motor neurons after stroke: a study of neuromuscular jitter by axonal microstimulation. , 1998, Electroencephalography and clinical neurophysiology.

[10]  H. Hermens,et al.  Motor unit properties in the biceps brachii of chronic stroke patients assessed with high-density surface EMG , 2009, 2009 4th International IEEE/EMBS Conference on Neural Engineering.

[11]  A R Upton,et al.  Functional changes in motoneurones of hemiparetic patients , 1973, Journal of neurology, neurosurgery, and psychiatry.

[12]  V Sahgal,et al.  Hemiplegic atrophy: Electrophysiological and morphological studies , 1981, Muscle & nerve.

[13]  S. Beniczky,et al.  Changes in muscle fiber density following a stroke , 2009, Clinical Neurophysiology.

[14]  W. Rymer,et al.  Characteristics of motor unit discharge in subjects with hemiparesis , 1995, Muscle & nerve.

[15]  F. Spaans,et al.  Denervation due to lesions of the central nervous system: An EMG study in cases of cerebral contusion and cerebrovascular accidents , 1982, Journal of the Neurological Sciences.