The Audibility of Low Vision Devices with Speech Output Used by Older Adults with Dual Sensory Impairment.

SIGNIFICANCE: The successful uptake, integration, and use of vision rehabilitation devices with speech output depend to a large part on their audibility. However, individuals with combined vision and hearing impairments are at a disadvantage when using devices that do not consider multiple impairments. PURPOSE: Sensory rehabilitation for individuals with combined vision and hearing impairment often relies on the use of assistive technology devices that use speech outputs (e.g., talking clock), but in individuals with dual impairment, their use is likely compromised by a concurrent hearing loss. The goal of this study was to evaluate the audibility of these devices in a population of individuals with acquired dual sensory impairment. METHODS: We measured the ability to correctly repeat speech output presented by three assistive technology devices (talking watch, calculator, scanner) and confidence levels in response accuracy in 24 participants with visual impairment only and in 22 individuals with dual sensory loss. Stimuli were presented at three volumes that were repeated one or four times. Participants were placed at a fixed distance of 74 cm from the sound source. RESULTS: The pattern of results was similar across the different devices, whereby an interaction of volume and repetition indicated that participants' accuracy to repeat a phrase and their confidence in their response improved with increasing volume, but more so at higher numbers of repetition (P < .05; ω, from 0.005 to 0.298). Participants with dual sensory loss generally had lower accuracy and confidence. CONCLUSIONS: Scores and confidence levels being very low across devices and users suggest that even participants with normal hearing for their age experienced a certain level of difficulty understanding speech output, confirming the need for better assistive technology device design.

Test-retest Variability of a Standardized Low Vision Lighting Assessment.

SIGNIFICANCE: Systematic lighting assessments should be part of low vision evaluations. The LuxIQ has gained popularity as an assessment tool, but its reliability has not been examined independently and is necessary for evidence-based vision rehabilitation. PURPOSE: Besides magnification, improved lighting levels are a common intervention in reading rehabilitation for individuals with low vision. Determining the appropriate lighting can be a complex and time-consuming task. The LuxIQ is a portable lighting assessment tool that can be used to systematically measure lighting preferences; however, there is little independent evidence to support its reliability in low vision rehabilitation. METHODS: One hundred nine control subjects (age, 18 to 85 years) and 64 individuals with low vision (age, 27 to 99 years) adjusted both the luminance and color temperature parameters on the LuxIQ while viewing a sentence on the MNREAD at their preferred print size for continuous reading. After 30 minutes, they were asked to repeat the same measurements. RESULTS: Using Bland-Altman plots, test-retest variability was calculated using the limits of agreement (LOAs). For illuminance, the LOA width was 2806 lux for control subjects and 2657 lux for visually impaired participants. For color temperature, the LOA width was 2807 K for control subjects and 2364 K for those with a visual impairment. Difference scores were centered near zero, indicating overall accuracy. CONCLUSIONS: The measurement of lighting preference lacks the precision necessary for clinical utility, given that the LOA for luminance ranged more than 2600 lux, with normally sighted and low vision participants. Such variability translates into a range of approximately ±40 or 50 W in an incandescent light bulb, depending on the luminance level, making it clinically difficult to narrow down the options for evidence-based lighting recommendations. Next steps are to examine whether the reading behavior of low vision clients is positively affected by interventions that are based on LuxIQ recommendations.