Portable infrared pupillometry using Pupilscan: Relation to somatic and autonomic nerve function in diabetes mellitus
- 70 Downloads
The relationship between dynamic pupillary function and peripheral nerve function was studied in 85 randomlyselected 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. Portable pupillometry using this device is currently the simplest method available for measuring a cranial autonomic pathway, though the measurements obtained with it are only weakly associated with the results of other tests of somatic and autonomic function in diabetes, and are unrelated to measurements of distal sudomotor function.
Key wordsPupillometry Diabetic neuropathy Autonomic neuropathy Sensory thresholds Sweat function
Unable to display preview. Download preview PDF.
- 1.Jordan WR. Neuritic manifestations in diabetes mellitus.Arch Int Med 1936;57: 307–366.Google Scholar
- 2.Rundles RW. Diabetic neuropathy.Medicine 1945;24: 111–160.Google Scholar
- 4.Neil HAW, Smith SA. A simple clinical test of pupillary autonomic function: correlation with cardiac autonomic function tests in diabetes.Neuro-ophthalmology 1989;9: 237–242.Google Scholar
- 5.Hayashi M, Ishikawa S. Pharmacology of pupillary responses in diabetics—correlative study of the responses and grade of retinopathy.Jpn J Ophthalmol 1979;23: 65–72.Google Scholar
- 9.Lowenstein O, Loewenfeld IE. Mutual role of sympathetic and parasympathetic in shaping of the pupillary reflex to light.Arch Neurol Psychiat 1950;64: 341–377.Google Scholar
- 11.Levy D, Abraham R, Reid G. A comparison of two methods for measuring thermal thresholds in diabetic neuropathy.J Neurol Neurosurg Psych 1989;52: 1072–1077.Google Scholar
- 15.Shahani BT, Halperin JJ, Boulu P, Cohen J. Sympathetic skin response—a method of assessing unmyelinated axon dysfunction in peripheral neuropathies.J Neurol Neurosurg Psych 1984;47: 536–542.Google Scholar
- 16.Levy DM, Rowley DA, Reid G, Abraham RR. Quantitative measures of sympathetic skin response in diabetes: relation to sudomotor and neurological function.J Neurol Neurosurg Psych 1992;55: 902–908.Google Scholar
- 21.Ryder REJ, Marshall R, Johnson K, Ryder AP, Owens DR, Hayes TM. Acetylcholine sweatspot test for autonomic denervation.Lancet 1988;i: 1303–1305.Google Scholar