The term Brain based Auditory and Visual Impairment (BAVI) can be used when an underlying neurological disorder is affecting the functioning of both vision and hearing. The eyes and ears may function from normal/near-to-normal to decreased levels, but the visual and auditory systems of the brain do not consistently process or interpret what the eyes see, and the ears hear. Along these lines, BAVI could occur in people with typical/near-to-normal hearing and vision as well as in people with combined vision and hearing loss/deafblindness.
Deafblindness is a disorder of combined vision and hearing loss, also known as dual sensory loss. Deafblindness has a varying combination of visual and hearing impairment in the same individual. The variables that influence this diversity include the severity of each sensory impairment (ranging from residual low vision to no light perception; hard of hearing to no sound perception), the order of onset (vision loss first, hearing loss first, simultaneous onset), and the timing of the onset (congenital sensory impairments, acquired sensory impairments, age-related dual sensory loss) (Dammeyer, 2014; Wittich, & Dumassais, 2025).
Deafblindness is a highly heterogeneous disorder. The most common causes of deafblindness in children and young adults are hereditary syndromes, such as CHARGE syndrome, Cornelia de Lange syndrome, Usher syndrome and Stickler syndrome, followed by cases with prenatal/congenital complications, such as cytomegalovirus infection, postnatal/non-congenital complications, such as meningitis and complications of prematurity, such as ischemia or hypoxia (Matsunaga, 2021).
A child with deafblindness with varying degrees of vision and hearing loss may have accompanying auditory and visual processing problems due to central nervous system disturbances. Underlying neurological disorders that impact the central nervous system, such as epileptic seizures, brain malformations or a concomitant brain injury may lead to difficulties in processing visual and auditory information in children with combined vision and hearing loss (Nicholas, 2020).
The likelihood of a proportion of children with visual processing difficulties also having auditory processing difficulties can be high. De Witt et al. (2018) have raised the question regarding the possible overlap between children with Cerebral Visual impairment (CVI) and children with Auditory Processing Disorder (APD). Given the difficulties in identification and diagnosis, it is not difficult to see why most children with visual processing disorders might not appear on the radar for auditory processing disorders (Aitken, 2010). Furthermore, there a very few data sets which contain this group, often it is either a CVI or APD problem.
To grasp the disorder of Brain based Auditory and Visual Impairment (BAVI), it is crucial to understand how the brain processes visual and auditory input in a bottom-up manner (upward neural pathways) and how the brain concurrently uses top-down processes (downward neural pathways) to support the rapid perception and interpretation of visual and auditory information. The idea that top-down influences modulate bottom-up processing in both vision and audition is supported by extensive empirical and theoretical work (Chaudhuri, et al., 2026).
Bottom-up processing starts with raw visual and auditory sensory impressions (i.e., light and sound) and it is the primary system engaged in perceptual processing, laying the foundation upon which top-down cognitive processes can apply their interpretative influence. At its core, top-down processing emphasizes that perception is not a passive reception of environmental stimuli. Top-down processing helps prioritize and organize incoming information and it is shaped by the salience of the sensory stimuli, prior experiences and expectations. The brain doesn't passively receive information; it actively generates models of the world and predicts incoming sensory data and updates those predictions with experience (Clark, 2013). In this way, sensory perception is crafted and constructed rather than acting as a passive receiver of reality. Consequently, the brain continuously coordinates sensory inputs from vision and hearing, to create a complex interplay and an integrated perceptual experience, which is shaped by interconnected bottom-up and top-down processes of a unified system (Saghravanian, 2025).
Through this perspective, BAVI is considered a complex disorder of impaired processing of both visual and auditory information due to brain-related issues and involves difficulties in this unified system of bottom-up and top-down processing. The impaired processing of this integrative system due to BAVI may be consistent with the combined disruption of lower-order auditory and visual processing at earlier levels (i.e. capturing specific visual & auditory sensory impressions and initial interpretations) and higher-order auditory and visual processing at later stages (i.e., applying auditory & visual attentional-memory processes and complex interpretations).
The disruption in the neural interplay between auditory lower-order & higher-order processing, together with visual lower-order & higher-order processing may create a malfunction consistent with BAVI. However, the severity of the visual and auditory processing difficulties of BAVI may vary within and across children due to different etiologies and to the extent of brain malfunctions. Importantly, BAVI can significantly cause developmental delays because it impacts on how the brain processes auditory and visual information. These developmental delays may stem from difficulties in visual and auditory lower-order functions, jointly with visual and auditory higher-order functions. In this manner, pediatric BAVI could be considered as a neurodevelopmental disorder, since it may begin during childhood and affect how the brain develops
To emphasize the uniqueness of the behavioural characteristics of children with deafblindness and BAVI, we use the term “DB-BAVI”. Children with DB-BAVI may not meet typical auditory and visual developmental milestones, often leading to challenges in motor skills (reaching, walking), communication and language, and cognition (learning, problem solving, understanding, comprehending). Especially, in a child with DB-BAVI, it is important to address the global impact of peripheral vision and hearing loss, together with central nervous system disturbances on the child for failing to meet typical developmental milestones.
Accordingly, it is necessary to develop an appropriate observational checklist to systematically record the presence or absence of specific behaviours associated with lower-order & higher-order auditory and visual processing. Especially for the purpose of identifying individuals who may be at risk for a BAVI disorder. As such, the Pediatric Brain based Auditory and Visual Impairment (P-BAVI) observational checklist can be used as a preliminary step in the evaluation of a brain based visual and auditory impairment (BAVI), as a way of determining if further, more comprehensive assessment is necessary. Furthermore, results from the P-BAVI evaluation can be used to guide individualistic interventions.
The P-BAVI could be also applied to children with other clinical disorders, such as in children diagnosed with autism spectrum disorder (ASD). ASD is a neurodevelopmental disorder characterized by difficulties with social interaction and restricted, repetitive patterns of behaviour, and can be regarded as disorder related to brain development that affects how children see, hear and perceive others and especially how they socialize with others. Atypical auditory and visual based behaviours with perceptual deficits have been explored in individuals with ASD, suggesting an impact of disrupted lower-order & higher-order operations on sensory processing (Marco, et al., 2011). Besides, identifying lower-order & higher-order sensory processing may serve as valuable findings for targeting therapeutic interventions for ASD.