Changes to online control and eye-hand coordination with healthy ageing

Area of Science:

• Neuroscience
• Motor Control
• Human Aging

Background:

• Goal-directed movements often involve saccades to target locations.
• Online control is crucial for correcting reaches, especially when targets shift mid-movement.
• Healthy aging impacts visual processing and motor control, but eye-hand coordination during online updating remains understudied.

Purpose of the Study:

• To quantify age-related differences in eye-hand coordination during online movement updating.
• To investigate how older and younger adults adjust reaches when targets move during the movement.

Main Methods:

• Participants performed a time-pressured double-step reaching task with target perturbations at 200, 400, and 600 ms.
• Eye and hand positions were tracked to analyze saccade latency, movement latency, movement time, reach characteristics, and eye-hand latency/accuracy.

Main Results:

• Both age groups successfully updated reaches for perturbations at 200 and 400 ms.
• All participants showed incomplete updating for the 600 ms perturbation.
• Older adults had longer saccade latencies and movement times, but comparable touch accuracy.
• Older adults exhibited more secondary saccades and shorter eye-hand latencies in perturbation conditions.

Conclusions:

• Online movement control appears qualitatively different in older adults.
• Compensatory mechanisms, like shorter eye-hand latencies, may be employed by older adults to maintain reach accuracy.
• Age-related changes in visuomotor processing influence the online updating of goal-directed movements.