David J. Schroeder

Effects of alcohol ingestion on tracking performance during angular acceleration.

Abstract : Most studies of the effects of alcohol on human performance involve static (absence of motion) situations. However, the addition of motion, involved in such activities as piloting an aircraft, might well produce impairments not usually obtained in static situations. The present study examined some of the effects of alcohol ingestion on visual tracking performance (eye-hand coordination) during angular acceleration. Following practice and base-line tests of tracking performance in both static (stationary) and dynamic (whole body angular acceleration) conditions, 10 subjects received orange juice which contained 2.0 ml of 100-proof vodka per kg of subject weight; another 10 drank orange juice with a few drops of rum extract added. Tests, conducted 1, 2, 4, 8, and 10 hours after drinking, were in total darkness with the exception of the visual display which was illuminated to recommended levels for cockpit instruments. Static tracking errors for Alcohol subjects were significantly higher than those of Control subjects only at the 4-hour session. However, Alcohol subjects made significantly more dynamic tracking errors than Controls during the 1-, 2-, and 4-hour sessions. These data suggest that eye-hand coordination may show little or no impairment following alcohol ingestion in static situations, yet may be seriously degraded during motion. (Author)

Influence of Alcohol on Positional Nystagmus over 32-Hour Periods

One of the clinical signs of acute alcohol intoxication is the presence of a positional alcohol nystagmus ( PAN). Based on the work of Plenkers,’ who noted that the direction of PAN was related to the time after drinking, and of Walter,’ who described two phases of that response, Aschan et ~31.~ conducted a detailed investigation of PAN using electronystagmography. They defined PAN I as a nystagmus beating in the direction of the lower ear (when the subject is lying on his side or when the subject rolls his head to one side while lying in a supine position), and PAN I1 as a nystagmus beating in the direction opposite the lower ear. Aschan et al.3 found PAN I to begin approsimately 30 minutes after the ingestion of alcohol and to persist for several hours, followed first by a latency period during which no positional alcohol nystagmus could be demonstrated, and then by PAN I1 which began about five to six hours after ingestion. The same authors reported PAN I1 to persist for various periods of time up to the fourteenth hour after alcohol ingestion.

Effects of Secobarbital and d-Amphetamine on Tracking Performance During Angular Acceleration

Abstract Thirty young men wore randomly assigned in equal numbers to one of the following groups: placebo (lactose), secobarbital (100 mg), or tj-amphetamine (l0 mg). The drugs or placebo wore administered in capsules in a double- blind procedure following practice at a tracking task and baseline determinations of tracking performance levels in both static (stationary) and dynamic (angular acceleration) conditions. Tests wore scheduled 1, 2, and 4 hours after capsule ingestion; all tests were conducted inside a St:lle-Werner rotator and were in total darkness with the exception of the illuminated tracking display. With the rotator stationary, d-amphetamino subjects performed significantly better than controls during the 2-hour and 4-hour post-drug sessions; no other static differences among the groups wore significant. However, during angular acceleration, secobarbital subjects made significantly more tracking errors and had significantly more vestibular nystagmus than both the control and the d-amphetami...

SOME EFFECTS OF CHANGES IN SPIRAL SIZE AND VIEWING DISTANCE ON THE DURATION OF THE SPIRAL AFTEREFFECT

Duration of the spiral aftereffect (SAE) was investigated with spirals of 2, 4, 8, 12, 14, and 16 inches in diameter. The distance of the spirals from the observers was varied to produce visual angles between 1°12′ and 18°56′ of arc. Data indicate that peak SAE durations occur approximately between 2° and 4° of visual angle.

Some Effects of Perceived Size, Retinal Size, and Retinal Speed on Duration of Spiral Aftereffect.

Measures of perceived size, perceived distance, and perceived stimulus speed of rotating spirals were obtained in addition to the duration of the spiral aftereffect. Two major conditions were used: Size Constant—a 4-in. spiral was positioned to subtend visual angles of 1/2°, 1°, 2°, 4°, or 8° with 7 rates of retinal speed (10-100 minarcs/sec.) used at each angle; Angle Constant —3 sizes of spirals were positioned so that each subtended visual angles of 2°, 4°, and 8° with physical speed held constant (75 rpm) in one case and retinal speed (45 minarcs/sec.) held constant in another. SAE durations were significantly affected by low retinal speeds, by small visual angles and by perceived size per unit of retinal size.