Loading…
Muscle spindle activity in the affected upper limb after a unilateral stroke
Weakness, loss of dexterity and exaggerated reflex responses to proprioceptive and cutaneous stimuli are typical features of hemiparetic stroke. Since the extent to which altered fusimotor drive contributes to these deficits has not been established, this study was designed to assess fusimotor funct...
Saved in:
Published in: | Brain (London, England : 1878) England : 1878), 1999-11, Vol.122 (11), p.2079-2088 |
---|---|
Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | Weakness, loss of dexterity and exaggerated reflex responses to proprioceptive and cutaneous stimuli are typical features of hemiparetic stroke. Since the extent to which altered fusimotor drive contributes to these deficits has not been established, this study was designed to assess fusimotor function in stroke patients by comparing three aspects of muscle spindle afferent behaviour (background discharge rate, responses to reflex inputs and responses to voluntary contractions) in 11 subjects affected by recent cerebrovascular lesions, with those in 18 healthy volunteers. The mean background discharge rates of muscle spindle afferents in the radial nerve when subjects attempted to relax the recorded limb completely were 6.6 ± 5.3 Hz (n = 26) in patients and 6.4 ± 6.1 Hz (n = 76) in control subjects. The variability of discharge rate of active afferents was also similar (0.12 ± 0.07 and 0.09 ± 0.10, respectively). Reflex activation of fusimotor neurons was assessed using trains of electrical stimuli to the superficial radial nerve or to the palm of the hand, and using natural skin stimuli. Neither type of cutaneous stimulation affected muscle spindle afferent discharge in the absence of an EMG response. During deliberate voluntary contractions muscle spindle discharge rates were enhanced similarly in both the control and patient groups, indicating that volitional drives could access fusimotor neurons in the patients. Qualitatively, spindle behaviour was similar in patients and control subjects. These findings suggest that fusimotor function is not disturbed any more or less thaln skeletomotor function in hemiparetic patients and it is concluded that fusimotor dysfunction probably contributes little to their deficit. |
---|---|
ISSN: | 0006-8950 1460-2156 |
DOI: | 10.1093/brain/122.11.2079 |