Comparison of sympathetic skin response with quantitative sudomotor axon reflex test in diabetic neuropathy.
The sympathetic skin response (SSR), the quantitative sudomotor axon reflex test (Q-SART), and cardiac beat-to-beat variability with respiration as measured by the expiratory/inspiratory ratio (E/I ratio) were studied in 39 patients with diabetic neuropathy of whom 33 also had one or more symptoms of autonomic involvement. In the lower extremities 87% of the patients with an absent SSR had an abnormal Q-SART (P less than 0.001), and 81% of patients with the SSR present had a normal Q-SART (P less than 0.02). The E/I ratio was abnormal in all but one of 23 patients with an absent SSR in the foot, and a normal E/I ratio was present only in those patients (n = 7) with the SSR present in hand and foot, and in an eighth patient who had SSR absent in the foot and present in the hand. A similar correlation was found between the E/I ratio and the Q-SART in the foot, although 4 of 25 patients with an abnormal foot Q-SART had a normal E/I ratio. We conclude that the concordance of results of the SSR and Q-SART supports the combined use of these tests to uncover early distal sympathetic failure in diabetic neuropathy.
Maselli
R A
RA
Department of Neurology, University of Chicago, IL 60637.
Jaspan
J B
JB
Soliven
B C
BC
Green
A J
AJ
Spire
J P
JP
Arnason
B G
BG
D000328:Adult; D003929:Diabetic Neuropathies / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D005712:Galvanic Skin Response; D006801:Humans; D008297:Male; D012018:Reflex / Q000502:physiology; D013545:Sweat Glands / Q000294:innervation; D013564:Sympathetic Nervous System / Q000503:physiopathology*