Wide range of etiologies or risk factors may contribute to peripheral vision and hearing problems and concomitant brain dysfunctions in the auditory and visual processing systems. Traumatic brain injuries (TBI), including concussion due to significant blast exposure may lead to central hearing and vision difficulties and cognitive dysfunctions simultaneously (Lew, et al., 2009). Frequently, these adult patients are informed that they do not have hearing and visual loss despite their perceived listening difficulties and visual perceptual deficits in their daily lives. The disorder of having typical/near normal visual and auditory acuity and yet experiencing visual and hearing difficulties in everyday life may often be misunderstood or mislabeled. Thus, it is necessary to understand acquired vision and hearing processing deficits in adult patients originating in central neural pathways or networks rather than in the peripheral eyes and ears. Generally, a clinical assessment that includes measures of peripheral hearing, peripheral vision, central auditory functions, visual processing functions and neuropsychological tests are essential in recognizing the relative effect of the two processing deficits in adults (Saunders & Echt, 2012).
Vision and hearing deficits are known outcomes of TBI and exposure to explosives may put veterans and military personnel at particular risk of developing visual and auditory processing disorders unrelated to ageing (Raza, et al., 2024). The effects of peripheral changes to ears and eyes and the deficits associated with auditory and visual processing in adults have been described in military war veterans because of combat blast exposures (Saunders & Echt, 2012; Brungart, et al., 2019) and in professional divers because of barotrauma or underwater explosions (Ergen et al., 2019). Furthermore, visual processing problems (i.e., misperceptions of object size, distance, and shape) and auditory processing problems (i.e., difficulties in perceiving where a sound is coming from/spatial problems; difficulties in the timing or order of sounds/temporal problems), have been described in space mission astronauts due to exposure to microgravity following several months in orbit (Clément et al., 2013; Navarro Morales et al., 2023; Avcı, 2024). A combination of other risk factors, such as reduced visual stimulation, elevated background noise, social isolation and prolonged confinement during spaceflight may act as environmental stressors, which in turn may impair perceptual and cognitive processing of visual-auditory stimuli (Taylor, et al., 2016).
Taking all this clinical evidence together, it can be suggested that the disorder of a combined auditory and visual processing impairment exists in adults due to various etiologies and risk factors. However, the profile of combined auditory and visual processing impairment in children can significantly differ from patterns or features described in adults.
The deficits seen in children with combined visual and auditory processing (pediatric BAVI) may be interconnected and can impact the child’s auditory lower-order & higher-order functions and visual lower-order & higher-order functions at any time. Pediatric BAVI can stem from various causes like premature birth, low birth weight, neonatal hypoxia or ischemia, viral infections during infancy, traumatic brain injuries, brain tumors, strokes, seizure disorders, congenital hydrocephalus, congenital brain anomalies/maldevelopment and genetic predispositions/risk genes. Risk genes are typically expressed during cortical development (Willsey, 2013). Hence with reference to genetic neurodevelopmental disorders with neurological implications (i.e., CHARGE syndrome), it is necessary to consider the likelihood of pediatric BAVI secondary to associated brain abnormalities.
Overall, pediatric BAVI is about the complex disorder of auditory and visual processing deficits and subsequently how it interferes with some or many aspects of information processing. Particularly, children with BAVI may struggle to process visual and auditory impressions consistently, including difficulties with visual and auditory perception, visual and auditory attention, as well as navigating complex visual and sound environments. Besides, BAVI may often lead to difficulties in noticing or responding instantly/rapidly to visual targets in overwhelming visual scenes and to auditory targets in challenging listening situations.
In conditions of irrelevant sounds or distracting background noise (auditory clutter), the listening brain of a child with BAVI may struggle to separate background noise from meaningful sounds, which can often lead to increased auditory fatigue. Similarly, in conditions of overwhelming presence of visual elements within a given space (visual clutter), the brain of a child with BAVI may require more effort to integrate multiple visual elements of a scene or extract meaningful motion from complex scenes, which can often lead to increased visual fatigue.
The auditory and visual processing difficulties of children with BAVI can negatively impact learning, independence and several areas of life. Frequently a child with BAVI may not meet typical auditory and visual developmental milestones and this could often lead to marked developmental delays.