PSYCHOPHYSIOLOGICAL DIAGNOSTICS IN ALCOHOL DEPENDENCY - FOURIER-ANALYSIS OF PUPILLARY OSCILLATIONS AND THE RECEPTOR TEST FOR DETERMINATION OF CHOLINERGIC DEFICIENCY

Mnestic disturbances in alcoholics may be related to cholinergic defic iency as well as to central nervous system inactivation. After instill ation of tropicamide, cholinergic receptors are blocked and pupillary dilatation occurs. It is assumed that the more severe the cognitive de terioration, the wider the pupillary dilatation. Pupillary oscillation s reflect central activation. Changes of pupillary diameter after topi cal instillation of tropicamide and pupillary oscillations were measur ed in 44 alcohol-dependent patients aged 40-55 years, diagnosed accord ing to the DSM-III-R as severe alcoholics (>7 symptoms), having been a bstinent for at least 3 weeks (objectively tested with carbohydrate-de ficient transferrin), compared with 18 healthy controls. The pupillary diameter of the left eye was measured eight times within 103 min, as were pupillary oscillations. Using Fourier analysis, the amplitudes of oscillations were measured in five frequency bands and the sum of the frequency bands was calculated. In addition, central activation was m easured during a calculation test at 3 and 103 min. The pupillary dila tation of 22% in alcoholics compared to 14% of normal controls after t ropicamide raises the question of a cholinergic deficit in alcohol dep endence. With regard to basic activation, measured by Fourier analysis of pupillary oscillations, alcoholics demonstrated significantly lowe r power (sum of the frequency bands) than controls at baseline and at 3, 20, and 40 min (P < 0.01) as well as at 60, 80, 100, and 103 min (P < 0.05). After a cognitive task, a difference between alcoholics and healthy controls was found at 3 min. Alcoholics showed lower basic act ivation and decreased cognitive activation. By means of cross-validati on, a differentiation between alcohol-dependent patients (n=44 and n = 42 respectively) and normal controls (n = 18) was possible.