Ability to Process Multisensory Information Is Impaired in Open Angle Glaucoma

Précis: Patients with glaucoma demonstrated deficiencies in their ability to process multisensory information when compared with controls, with those deficiencies being related to glaucoma severity. Impaired multisensory integration (MSI) may affect the quality of life in individuals with glaucoma and may contribute to the increased prevalence of falls and driving safety concerns. Therapeutic possibilities to influence cognition in glaucoma should be explored. Purpose: Glaucoma is a neurodegenerative disease of the optic nerve that has also been linked to cognitive health decline. This study explored MSI as a function of glaucoma status and severity. Methods: MSI was assessed in 37 participants with open angle glaucoma relative to 18 age-matched healthy controls. The soundinduced flash illusion was used to assess MSI efficiency. Participants were presented with various combinations of simultaneous visual and/or auditory stimuli and were required to indicate the number of visual stimuli observed for each of the 96 total presentations. Central retinal sensitivity was assessed as an indicator of glaucoma severity (MAIA; CenterVue). Results: Participants with glaucoma performed with equivalent capacity to healthy controls on unisensory trials (F_1,53= 2.222, P=0.142). Both groups performed equivalently on congruent multisensory trials involving equal numbers of auditory and visual stimuli F_1,53=1.032, P= 0.314). For incongruent presentations, that is, 2 beeps and 1 flash stimulus, individuals with glaucoma demonstrated a greater influence of the incongruent beeps when judging the number of flashes, indicating less efficient MSI relative to agematched controls (F_1,53=11.45, P<0.002). In addition, MSI performance was positively correlated with retinal sensitivity (F_3,49=4.042, P<0.025), adjusted R²= 0.15). Conclusions: Individuals with open angle glaucoma exhibited MSI deficiencies that relate to disease severity. The type of deficiencies observed were similar to those observed among older individuals with cognitive impairment and balance issues. Impaired MSI may, therefore, be relevant to the increased prevalence of falls observed among individuals with glaucoma, a concept that merits further investigation.