Afferent pathways of sympathetic skin response in spinal cord: a clinical and electrophysiological study.
BACKGROUND
Sympathetic skin response (SSR) recording is an established test of sudomotor autonomic functions. However, knowledge of its pathways in spinal cord is putative.


OBJECTIVE
This study involved subjects with isolated spinal cord lesions to evaluate the afferent pathways of SSR.


METHODS
Clinical examination was done according to standard neurological classification of spinal cord injury. Electrophysiological evaluation included: (1) conventional nerve conduction studies to exclude peripheral nerve lesions, (2) scalp somato-sensory-evoked potentials (SEP) with posterior tibial nerve (PTN) stimulation and (3) SSR recording from palm by stimulating supra orbital nerve (SON) at forehead, and PTN at ankle. Subjects with absent SSR in palm to SON stimulation were excluded. In such patients, the afferent tracts were considered abnormal when SSR was absent in palm on stimulation of PTN.


RESULTS
Among 37 subjects (age-28.1+/-12.8 years), the afferent tracts of SSR were affected in 13. Sparing of afferent SSR tracts correlated with preservation of bladder sensations (P<0.01). There was no correlation between SSR and SEP.


CONCLUSIONS
Spinal cord lesions frequently involve afferent tracts of SSR. Spinal afferents of SSR are closely related with tracts of bladder sensations and are different from pathways for SEP.
Nair
K P
KP
Department of Psychiatric and Neurological Rehabilitation, National Institute Of Mental Health and Neurosciences, Hosur Road, Bangalore 560 029, India.
Taly
A B
AB
Rao
S
S
Murali
T
T
D000293:Adolescent; D000328:Adult; D000344:Afferent Pathways / Q000503:physiopathology*; D020211:Autonomic Dysreflexia / Q000473:pathology / Q000503:physiopathology; D002648:Child; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D010525:Peripheral Nerves / Q000503:physiopathology; D011379:Prognosis; D020127:Recovery of Function / Q000502:physiology; D012018:Reflex / Q000502:physiology; D012867:Skin / Q000294:innervation*; D012879:Skin Physiological Phenomena; D013116:Spinal Cord / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000473:pathology / Q000503:physiopathology*; D013546:Sweating / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000503:physiopathology*