Transcutaneous electric nerve stimulation reduces neglect-related postural instability after stroke.
OBJECTIVE
To test the existence of a neglect-related component of postural imbalance in some stroke patients to determine whether neglect patients (1) show worse postural control compared with nonneglect patients and healthy subjects and (2) have latent postural capacities that could be unmasked by an appropriate somatosensory manipulation.


METHODS
Intervention study with and without transcutaneous electric nerve stimulation (TENS).


METHODS
Rehabilitation center research laboratory.


METHODS
Twenty-two stroke patients (mean age, 58.3 +/- 2.5yr; average days since stroke, 83.2d) and 14 age-matched healthy subjects. Stroke patients were subdivided into 3 groups: 6 with spatial neglect and 16 without (8 with left lesion, 8 with right lesion).


METHODS
All participants were subjected to a dynamic balance task, performed while sitting for 8 seconds on a laterally rocking platform. Seated on this mobile support, they were asked to maintain actively an erect posture, sitting as still as possible. In patients, TENS was applied on the contralesional side of the neck during the postural task. An effective stimulation (intensity corresponding to the threshold of perception, TENS+) was compared with a placebo stimulation (.01 x threshold of perception, TENS-).


METHODS
Postural performance in each trial was monitored by using 2 criteria: the number of aborted trials caused by loss of balance, and the angular dispersion of the support oscillations in roll. The latter criterion, which increased with body instability, was defined as 2 standard deviations of the angular distribution.


RESULTS
Patients showing neglect displayed pronounced postural instability compared with other patients and controls. Although dramatic postural instability in the neglect patients was spectacularly and systematically reduced with TENS, no effect was observed in patients without neglect.


CONCLUSIONS
This is among the first studies to provide clinical evidence supporting the "postural body scheme" concept.
Pérennou
D A
DA
Départment de Médecine Physique et Réadaptation du CHU de Nîmes, Unité de Rééducation Neurologique, Le Grau du Roi, France. perenn@iurcl.montp.inserm.fr
Leblond
C
C
Amblard
B
B
Micallef
J P
JP
Hérisson
C
C
Pélissier
J Y
JY
D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010468:Perceptual Disorders / Q000503:physiopathology / Q000534:rehabilitation*; D004856:Postural Balance; D011187:Posture; D012044:Regression Analysis; D012678:Sensation Disorders / Q000503:physiopathology / Q000534:rehabilitation*; D012815:Signal Processing, Computer-Assisted; D020521:Stroke / Q000503:physiopathology; D000071939:Stroke Rehabilitation; D004561:Transcutaneous Electric Nerve Stimulation