Portable infrared pupillometry using Pupilscan: relation to somatic and autonomic nerve function in diabetes mellitus.
The relationship between dynamic pupillary function and peripheral nerve function was studied in 85 randomly-selected diabetic patients and 67 age-matched normals using a portable infrared pupillometer (Pupilscan Version 5). Seven measurements were chosen to represent different components of the pupillary constriction-redilatation curve after a standardized light stimulus. Constriction latency was significantly prolonged in diabetic patients (p = 0.05), as was time to 63% redilatation (p = 0.001). Thermal thresholds at the feet weakly correlated with relative reflex amplitude (warm: r = -0.22, p = 0.05; cool: r = -0.23, p = 0.05), but vibration perception thresholds were more strongly associated with constriction and redilatation velocity (r = -0.42, p = 0.001; r = -0.28, p = 0.03). Among the cardiovascular autonomic function tests, only respiratory R-R variation correlated with constriction velocity (r = 0.47, p < 0.001), and Valsalva ratio with redilatation velocity (r = 0.25, p = 0.04), but postural systolic blood pressure change was also correlated with reflex amplitude and latency time (r = -0.42, p < 0.001; r = 0.41, p = 0.001). There were no significant associations with three measures of sweating function in the feet. Pupil measurements were abnormal in 4-11% of diabetic patients, while other neurological tests were abnormal in 8-35%, consistent with the length-dependence of diabetic neuropathy. Median coefficients of variation were 2.0-7.2% in diabetic patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Levy
D M
DM
Department of Diabetes and Endocrinology, Central Middlesex Hospital, Park Royal, London, UK.
Rowley
D A
DA
Abraham
R R
RR
D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007259:Infrared Rays; D008297:Male; D008875:Middle Aged; D010525:Peripheral Nerves / Q000503:physiopathology; D011681:Pupil Disorders / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology