Dual sensory loss affects confidence in navigation and sound localization

According to a recent multi-institute PLOS One study led by the Multisensory Research Lab at the Wilmer Eye Institute, Johns Hopkins Medicine, time of hearing loss onset is a key determinant of patient confidence and self-reported sound localization abilities - the ability to perceive and locate objects in an environment - even in individuals who use hearing aids or who have received vision rehabilitation training. 

The National Institutes of Health-supported study highlights factors that shape how people with dual sensory loss (combined hearing and vision loss) engage with their environments and identifies opportunities for health care practitioners to improve patient quality of life. 

Previous CDC research estimates that approximately 7 million adults in the United States live with vision loss or blindness, and 30 million individuals ages 12 or older have hearing loss in both ears. While the prevalence of dual sensory loss increases significantly with age, little is known about how it affects patient confidence and skill development - two traits essential for independent living. 

Controlled lab studies exist, but they do not fully capture how blind individuals with hearing loss navigate real-world environments, or why they may hesitate to enter certain complex spaces despite having measurable sound localization skills. With our study, we aimed to capture patient attitudes on their own navigational skills and the compensatory strategies they use in their daily lives." 

Yingzi Xiong, Ph.D., Barbara Simerl Rising Professor of Low Vision, Wilmer Eye Institute

In collaboration with the Minnesota Laboratory for Low Vision Research and the Envision Low Vision Rehabilitation Center, Xiong's research team recruited 58 adults with total or near-total blindness for the study. Among the participants, 28 self-reported typical hearing and 30 self-reported hearing loss. Additionally, 94% of study participants received formal orientation and mobility training - a specialized type of vision rehabilitation training that teaches individuals who are blind or visually impaired how to build a mental map of their environment and navigate safely. 

Each participant completed the Dual Sensory Spatial Localization Questionnaire (DS-SLQ), a standardized tool previously developed by Xiong's team to assess both the perceived and performed spatial localization abilities of people with vision and hearing loss when completing everyday tasks. In this study, responses were used to evaluate how blindness onset, hearing loss onset, residual vision and hearing aids shaped perceived sound localization abilities. 

Reviewing DS-SLQ responses, the researchers found adults who experienced early onset blindness without hearing loss reported the highest confidence in their skills. Confidence was lower among adults who were blind and reported hearing loss, and those who lost their hearing early in life reported the lowest sound localization abilities of all participants. 

"People with dual sensory loss may feel less confident or less motivated to adopt new hearing strategies for everyday tasks," says Prachi Agrawal, M.D., M.P.H., study first author and postdoctoral research fellow in the Xiong lab. "By identifying these barriers, providers can tailor rehabilitation strategies to build confidence and support targeted skill development." 

Although hearing loss was linked to sound localization difficulties, the researchers found adults who used hearing aids did not report higher confidence or navigational skills than the other participants. 

"Hearing aids are a common intervention used for patients with hearing loss, but currently available devices primarily focus on improving speech perception," says Xiong. "Here, we saw that patients did not report on-the-market hearing aids were helpful for environment navigation, similar to our previous research." 

Based on their study findings, Xiong's research team suggests that clinicians should account for hearing status during vision rehabilitation training and carefully identify areas of fear or hesitancy that may be addressed through individualized care. 

"About 40% of patients who seek vision rehabilitation in the U.S., including at the Wilmer Eye Institute's Lions Vision Research and Rehabilitation Center, also have hearing loss," says Xiong. "We believe understanding how patients perceive their own sound localization skills will help providers meet their needs and establish skills to live their lives." 

The study was supported by the National Institutes of Health (K99/R00EY030145), an Envision Fellowship and a Research to Prevent Blindness award.