Adaptive Tracking Task

Background

Adaptive Tracking tasks are psychomotor tests to measure visuomotor coordination and vigilance. The paradigm was first introduced by R. G. Borland and Anthony N. Nicholson in 1984 who set out to create a sensitive, objective measurement tool for the lingering effects of psychotropic drugs on visuomotor coordination and vigilance that can have severe consequences on operational performance, such as flying an airplane or driving a car. Adaptive Tracking tasks are to this day widely utilized in clinical and cognitive research to evaluate the effects of sleep deprivation, fatigue, alcohol, or psychoactive medications.

The basic task in adaptive tracking is to keep one's index finger (or joystick/computer mouse/stylus pen) centered on a moving disk. In contrast to the Pursuit Rotor Task, in which the speed of the disk is predictable in its speed and movement pattern, the direction of the moving disk in Adaptive Tracking tasks is unpredictable and its speed is continuously updated based on a participant's performance. Correct performance speeds up the disk; errors (e.g. losing the disk) slows it down. The implemented adaptive algorithm keep the tracking speed to an individual's absolute performance threshold and is considered a highly precise way to measure mental fatigue, attention, and impairments due to drugs.

The Millisecond Adaptive Tracking task is optimized for running the task on touchscreen devices. The default settings specify an absolutely sized active canvas that is approximately ipad sized. The active game canvas is presented in black anchored by the gray inactive portions of the screen, so that the black active canvas not only has the absolute same size on each screen but also appears that way. Screens that are too small receive an error message and the task prematurely terminates (Note: the dimensions of the active canvas can be easily adjusted to a different size).

If a touchscreen is detected, the mouse cursor is turned off and participants need to engage with the task using fingers/stylus pens as the tracking device. On non-touchscreens, the mouse cursor is turned on and participants need to engage with the task using the computer mouse cursor to track the circle. The calculation of the pseudo-random movement coordinates is based on the tracking task procedure described by Alexander Foulkes and R. Chris Miall in 2000. Tracking speed is continuously adjusted by adjusting the time that the disk requires to reach 'inflection' points (points at which direction changes). Speeds are adjusted using a 'one up, two down' simple staircase procedure, which results in a ~70% on-target performance overall.

Task Procedure

Participants are introduced to the task and work on a 30 second practice session before starting the test session. The default duration of the test session is set to 4 minutes. The basic task is to track a moving yellow disk with the finger/stylus/mouse cursor without losing it. Under the cover, the test block consists of a sequence of tracing trials that present the yellow disk as an animated object that travels from one (inflection) point (P1) to the next (P2), at a pre-determined speed. Every 100ms (or earlier if the next inflection point has been reached), the tracking accuracy is checked, and the travel speed is adjusted accordingly up or down. Once the inflection point has been reached, a new random inflection point is calculated. The script checks the coordinates of the participant's input device (finger/stylus/mouse cursor) in relation to the center coordinates of the disk approximately every 17ms. At the end of each tracking trial, the proportion of times that the tracking coordinates were off the disk determines the current tracking accuracy (85% and more on => correct; less than 85% => error) and is used to continuously adjust the traveling speed via the 'one up, two down' staircase procedure. On touchscreen devices, if a lift-off response is registered, the trial prematurely ends, participants are reminded to always keep their fingers on the screen, and the speed is reduced automatically as long as the finger is off the target. Mouse cursors automatically always stay on screen, and no reminder is needed. The number of lift-offs on touchscreen devices is noted in the data files.

What it Measures

The Adaptive Tracking task measures visuomotor coordination and vigilance

Psychological domains

• Visuomotor Coordination: The ability of the brain, eyes, and body to work together on a task
• Vigilance: Ability to maintain focus on a continuous repetitive task over a long time.

Main Performance Metrics

• Speed Score: mean tracking speed relative to minimum disk speed
• Average Speed: the mean/median tracking speed in mm/ms during the test round
• Recovery Duration: the mean/median duration in ms that participant spent in off-target mode during the test round

Psychiatric Conditions

The following patient groups have been tested with Adaptive Tracking Tasks

• Parkinson’s Disease (PD)
• Mild Cognitive Impairment (MCI)
• Attention Deficit Hyperactivity Disorder (ADHD)
• Schizophrenia
• Mood Disorders
• Pharmaceutical Studies on Healthy Adults

References

Search Google Scholar for peer-reviewed, published research using the Inquisit Adaptive Tracking Task.

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Borland, R. G., Nicholson, A. N. Visual motor co-ordination and dynamic visual acuity. Br J Clin Pharmacol. 18, Suppl 1. 69S-72S (1984).

Van steveninck AL, Schoemaker HC, Pieters MS, Kroon R, Breimer DD, Cohen AF. A comparison of the sensitivities of adaptive tracking, eye movement analysis and visual analog lines to the effects of incremental doses of temazepam in healthy volunteers. Clin Pharmacol Ther. 1991;50(2):172-80.

Foulkes, A. J. M., & Miall, R. C. (2000). Adaptation to visual feedback delays in a human manual tracking task. Experimental Brain Research, 131(1), 101–110. https://doi.org/10.1007/s002219900286