Test-retest reliability of the Dynavision apparatus.

The Dynavision apparatus was developed to measure and train a number of psychomotor s u s , including visual scanning, peripheral visual awareness, and visuomotor reaction time (Performance Enterprises, 1992). Although several rehabilitation and human performance centers currently use the apparatus in occupational therapy and sport-related training, no reports of reliability have been published. The Dynavision apparatus consists of a wall-mounted board (120 cm x 120 cm) housing 64 small square buttons arranged in a pattern of five nested rings. One training exercise is known as Mode B. In this exercise, random buttons illuminate one at a time and remain lit for a set time period (.I, .25, .4, .5, .75, or 1.0 sec.) before extinguishing and reappearing at new locations. A user, standing before the apparatus, must strike illuminated buttons before they extinguish; at all timesthe user fixes his eyes directly forward and uses his peripheral vision to 'see' illuminating buttons across the span of the board. A beep signals a successful hit, and the total number of hits is recorded by the apparatus. In general, more hits reflect faster visuomotor responses and 'better' performance. Mode B may take 30 or 60 sec. Other modifications of the task involve the use of shorter time intervals for button illumination) which increases the perceived speed of light movement and therefore increases task difficulty. I n addition, a small liquid crystal display (LCD) near the centre of the board can be set to display up to seven computer-selected digits for brief, preset exposure periods (.01, .05, .1, .25, .4, .5, .75, or 1.0 sec.) at 5-sec. intervals. Subjects can be instructed to call out or manipulate digits, e.g., add or multiply, during a button-striking task, thereby increasing the complexity of the task. The current study examined the test-retest reliability of two Mode B tasks across several testing occasions (TI, T2, and T3), with each occasion separated by two weeks. O n each occasion subjects were given two trials (one 'warm-up' and one test trial). The two Mode B tasks were (1) a 'speed'