Purpose
Traditionally, research into the usability of assistive devices that aid in sensory loss consider vision and hearing separately. However, changes in the demographics of rehabilitation clients and the complexity of their health status call for a more inclusive approach, which considers multiple impairments in parallel. We are interested in task realization of individuals with both vision and hearing loss when interacting with assistive listening devices. Specifically, we were curious as to whether visibility, dexterity and complexity of the task interfere with the success and speed of using a device. We also examined if a minimal rehabilitation intervention can improve ability and speed of device use.
Methods
Twenty-nine older adults with low vision (Mean VA = 20/202, age 67-95), 31 with vision and hearing impairment (Mean VA = 20/247, age 60-100), and 12 age-matched controls (VA > 20/30, age 66-87) were asked to: assemble a pocket-talker, use an amplified telephone, and set daylight savings time on a talking clock. The two experimental conditions were “out of the box” without instructions versus a two-minute explanation of how the device works. Mistakes, time to completion, dexterity (assessed with Purdue Pegboard), and cognition (blind version of Montreal Cognitive Assessment) were recorded.
Results
Both groups with sensory impairment made more mistakes on all three tasks in the out-of-the-box condition, p > .05, respectively. Mistakes and time to completion were reduced after the explanation of the devices for all groups, p > .05, respectively. Using logistic regression, lower visual acuity, lower cognitive scores, and higher age were predictive of task failure, depending on the task complexity and the number of consecutive steps involved. When comparing performance speed between individuals who completed each task successfully and those who did not, the success group generally performed faster.
Conclusions
Even minimal instruction (2 minute explanation) on the utilization of assistive devices improved success and speed. In the combined vision and hearing group, however, not all difficulties could be resolved, indicating that additional resources (and time) are required. Both vision and hearing care professionals should be cognizant of utilization limitations for clients with combined sensory loss when using assistance technologies.