Brain based Visual and Auditory Impairment (BAVI) is about how the brain causes combined auditory and visual processing difficulties. The notion of conceptualizing BAVI in a unified fashion, rather than as two distinct disorders incidentally presented in the same person, is relatively recent. Impairment as result of BAVI creates difficulties for a person to process and interpret both sound and vision in a separated or integrated manner. Thus, BAVI may create a functional impairment that is much more complicated than the combination of the two single processing impairments, Cerebral Visual impairment (CVI) and Auditory Processing Disorder (APD). However, BAVI may share some similar impairment characteristics with both CVI and APD.
Cerebral Visual impairment (CVI) is fundamentally a brain-based visual processing disorder that makes it difficult to process and understand visual information. CVI is widely used as an umbrella term for a wide variety of visual difficulties due to visual dysfunction in early childhood that results from a wide range of developmental disorders and brain injuries (Zihl & Dutton, 2015). It is a disorder associated with heterogeneous visual dysfunctions arising from brain injury or abnormality (Philip & Dutton 2014). Sakki and colleagues (2018) have described CVI as heterogeneous visual dysfunctions of multiple pediatric etiologies that originate in the brain rather than in the ocular structures or anterior visual pathways. Furthermore, it is characterized by deficits of visual function and functional vision caused by neurologic damage or maldevelopment of the visual processing areas in the brain (Gordon et al., 2024).
CVI is considered a neurodevelopmental disorder and may be comorbid with other neurodevelopmental disorders (Chang, et al., 2024). A vast majority of CVI children have comorbid neurological disorders and deficits including neurodevelopmental disabilities, epilepsy/seizures, cerebral palsy, hydrocephalus, genetic changes and periventricular white matter disease (Philip & Dutton, 2014; Jimenez-Gomez, et al., 2022)
CVI represents a lifelong condition characterized by a complex amalgam of impairments in lower- and/or higher-order visual functions caused by congenital or acquired brain injury, malformation, or malfunctioning of the visual processing networks, rather than any potentially co-occurring impairment of the peripheral visual system. The visual impairments and/or dysfunctions are heterogeneous and complex and impact the ability to perform vision-related or visually guided activities. This, together with the often-co-occurring neurodevelopmental impairments, can seriously limit functioning, educational performance, daily activities, and participation. (Micai et al., In Press). Consequently, the visual difficulties in CVI may manifest as both visual lower-order and higher-order deficits, leading to characteristic behaviors in affected individuals. The lower-order visual deficits may include impaired visual acuity, reduced contrast sensitivity or visual field deficits, acuity, whilst the higher-order deficits may include impaired face and object recognition, difficulties with visual-spatial orientation or impaired visual attention (Monteiro, et al., 2025). Moreover, children with CVI may have distinct difficulties, such as the ability to integrate multiple visual elements of a scene to achieve visual overview (global visual selective attention deficit) (Hokken, et al., 2024). Global visual selective attention is essential for navigating crowded environments and recognizing objects or faces. In addition, CVI children may display difficulties in the ability to integrate many individual motion signals of a large visual area to understand the coherent movement of a whole object or scene, like seeing a flock of birds move as one (global motion perception deficit) (Pamir et al., 2021)., Global motion perception is essential for extracting meaningful motion from complex scenes and is also necessary for navigation and avoiding obstacles during navigation.
It is crucial to highlight that CVI deficits are prone to significant individual differences and can exist in varying combinations and severities. Accordingly, CVI should be considered a spectrum disorder, not a single diagnosis, where the specific type of visual deficit and its severity depend on the location and extent of brain damage affecting visual processing (Chokron & Dutton, 2023). Statistical analyses of children with suspected or diagnosed congenital CVI have revealed three subgroups (A1, A2, B), with discrete profiles and a continuous spectrum of severity including visual acuity reduction from Group A1 to B in direction of greater severity and with Group A2 as intermediate (Sakki et al., 2021), although the exact number of subgroups is still debated.
Auditory Processing Disorder (APD) on the other hand, is a deficit in the way sounds are analyzed by the brain (Dillon and Cameron, 2021). APD often leads to difficulties in the brain`s ability to organize sound processing and interpret auditory signals, even with normal hearing. It is characterized by poor perception of both speech and non-speech sounds (Moore et al., 2011). Specific deficits in auditory rhythm perception, that is problems in the perception of regularly timed sound sequences have also been reported in children with APD (Sidiras, et al., 2019). Besides, children with APD have difficulty making sense of sounds including speech sounds, leading to trouble following verbal instructions, especially in challenging listening situations. Auditory processing difficulties become more pronounced in noisy environments or when multiple people are talking simultaneously from different directions.
APD represents a constellation of inconsistent responses to sounds, with or without normal pure-tone hearing sensitivity (Tepe, et al., 2023). Relatedly, inconsistent responses to sounds and poor speech clarity are also reported in an Auditory Neuropathy Spectrum Disorder (ANSD), which involves problems of sending sound from the inner ear to the brain, due to specific damage to inner hair cells or the auditory nerve fibers (i.e., deficient transmission of auditory signals). On the contrary, APD is a listening problem where the brain struggles to interpret sounds, especially in overwhelming listening conditions, such as in background noise (i.e., deficits in the neural processing of auditory information). APD manifests as an impaired processing of auditory information leading to significant auditory comprehension challenges, especially evident in learning tasks (Gitto, et al., 2025).
APD has been described as a specific deficit in processing of auditory information along the central auditory nervous system, including bottom-up and top-down neural connectivity. (Sidiras, et al., 2019). Accordingly, auditory function does not rely solely on the integrity of the ascending auditory neural pathways (upward route) but also depends on the connectivity of the descending auditory neural pathways (downward route), which include the brain’s cognitive centers. It has been hypothesized that deficits seen in children with impaired auditory processing might not only arise from deficits in the upward auditory pathway (bottom–up processes), but also from impaired downward auditory pathways (top–down processes) possibly also affecting the efferent central auditory system, such as structures that mediate auditory processing by attention and memory (Moore, 2012). Accordingly, the listening difficulties of children with APD are often not fully explained by disordered transduction in the cochlea or abnormal early processing along the auditory brainstem pathway, but most likely that listening challenges are associated with how auditory information is processed in the cortex (Ahmadi, et al., 2024).
One of the most common symptoms of APD is poor listening skills, which often leads to a listening difficulty. Poor listening skills are characterized by difficulty distinguishing speech from background noise, decreased attention to auditory information, need for excessive verbal repetitions, distracted in listening situations, restless during conversations, difficulty localizing the source of the speech signal and difficulty to discriminate among speech sounds (Vandergrift, 2004). When listening breaks down, children can miss key instructions, appear inattentive and distracted, and fall behind academically (Chermak, et al., 2002).
Listening is the process of hearing with intention and attention (Kiessling, et al., 2003), with an intent to extract information. Accordingly, listening involves a complex interplay between lower-order processing (i.e., hearing sound details, distinguishing similar sounds, determining the sequence or timing order of sounds,) and higher-order processing (i.e., interpreting sounds, auditory‑based language processing, attention to sounds, remembering auditory sequences) (Khavarghazalani et al., 2024). Especially the allocation of auditory attentional resources and auditory working memory play a vital role in the higher order processing of listening (Mattsson, et. al., 2019). Hence, in overwhelming listening conditions, the degraded or ambiguous auditory signal places increased demands on the listener’s auditory attention or auditory working memory to achieve accurate perception. While listening was initially examined as a singular ability, recent examinations have framed listening as a dynamic network of auditory, linguistic and cognitive processes that develop throughout childhood (Gurteen, et al., 2026; Obuchi, et al., 2026)
Furthermore, listening involves identifying the source of the sound (i.e., sound localization) and is influenced by the acoustic quality in the listening environment. Sound localization is how the brain figures out where a sound comes from in space, spatial processing. Sound localization involves the precise relative intensity and timing between the two ears (i.e., binaural cues), as well as neural encoding of sound locations, especially the processing of sound sources in the cortex (Tian, et. al., 2021). It involves several specialized and complementary mechanisms that go beyond the mere detection of sound sources, and it involves multilayered sound processing at both perceptual level and in higher level integrative functions, especially in the integration of auditory spatial cues (Alzaher, et al., 2026). Practically, sound localization is essential for safe navigation in the environment, and plays a central role in communication (Alzaher, et al., 2026).
Regarding, the acoustic quality in the listening environment (i.e., room acoustics) factors such as excessive reverberation or high background noise can mutually disrupt a child`s ability to listen effectively (Zhou, et al., 2025). Although several parameters can be used to characterize room acoustics, reverberation is the most dominant one. Findings highlight that poor room acoustics may intensify cognitive fatigue and listening difficulty (Breuer, et al., 2022). Furthermore, difficulties in listening vary significantly between indoor and outdoor environments due to differences in acoustics and types of background noise (Mercugliano, et., 2025). Hence, problems with sound localization and listening difficulties in poor acoustic environments represent debilitating symptoms of APD.
Children with APD often experience confusion and difficulty with everyday listening tasks. Adequate listening skills rely not only on auditory processing but may also depend on multiple other foundational skills such as hearing levels, cognitive function and language ability (Gudkar, et al., 2024). Children with difficulties in listening might therefore have difficulties with one or more of these foundational skills which can be caused by underlying deficits in multiple domains such as deficits in auditory processing, language, cognition and spatial processing (Dillon, & Cameron, 2021). Furthermore, some of these underlying deficits may be the cause of others, hence creating a cascading effect. For example, protracted or repeated middle ear infections during the first five years of life may have left a lasting spatial processing difficulty that affects the child’s ability to understand speech in noisy environments, thereby slowing the rate of language acquisition. In turn, that deficit in language ability then makes it harder to fill in the gaps when listening to speech in noise (Dillon et al., 2025).
Current scientific understanding of APD is complex and has remained a controversial topic within audiology, with limited consensus and various approaches to the exact definition or diagnostic standards of APD (Wilson & Arnott, 2013). Therefore, an integral approach for understanding listening difficulties and their interconnected links to a range of audiological factors (e.g. hearing acuity and auditory processing) and non-audiological factors (e.g. attention and language abilities) are needed (O'Hara & Mealings, 2018; Seeto, et al., 2021; Gudkar, 2024). The current understanding of auditory processing is rooted in the theoretical framework of complex interactions between the peripheral and central auditory nervous systems and supports the idea that auditory processing is multidimensional and consists of distinct but connected skills (Shaikh, et al., 2026).
A high proportion of children with APD have comorbidities, thus, suggesting a complex connection between listening difficulties and cognitive or language deficits (Keith, et al., 2019). Attention deficits in children with APD appear to be centered around the auditory modality (Stavrinos, et al., 2018). Besides, listening difficulty linked to developmental language disorders has been characterized by an impaired processing of attended speech rather than a generalized auditory disengagement (Kojima et al., 2026).
Regarding APD and listening difficulties, the British Society of Audiology Position Statement and Practice Guidance on Auditory Processing Disorder (Moore et. al., 2018) has classified APD into three categories: 1) Developmental APD (cases presenting in childhood with listening difficulties, but with normal audiometric hearing and no other known etiology or potential risk factors), 2) Secondary APD (cases where listening difficulties occur in the presence, or as a result of either transient or permanent peripheral hearing loss) and 3) Acquired APD (cases where listening difficulties are associated with known medical causes, such as a brain lesion or abnormalities). Listening difficulties in acquired APD due to neurological etiologies have been reported in children with epilepsy (Beshr et al., 2025), children with identified brain lesions (Matos, et al., 2018) and in young children with post-concussion (Bonacina, et al., 2024).
By and large, CVI is a problem with visual processing in the brain. Similarly, APD is a problem with auditory processing in the brain (i.e. listening difficulty). Brain based auditory and visual impairment (BAVI) may share similar characteristics with the different subgroups of CVI and the categories of APD. Like CVI and APD, BAVI involves a breakdown in the complex interplay between lower-order processing and higher-order processing due to brain-related issues, resulting in a collection of varied functional deficits.
Nevertheless, pediatric BAVI should be considered as a distinctive neurodevelopmental disorder that creates a functional impairment that is much more complicated than the combination of CVI and APD. Thus, BAVI is not merely the sum of separate visual and auditory processing disorders, but rather a distinct clinical disorder that diminishes the ability to process both visual and auditory information.
The profile of BAVI can have diverse manifestations and unique characteristics. Specifically, the processing problems of children due to pediatric BAVI may fall on a spectrum and co-occur in other neurodevelopmental disorders. It might be challenging, yet important, to differentiate BAVI from other neurological or neurodevelopmental disorders. Due to shared neurodevelopmental pathology, many children with BAVI may also experience comorbid motor, language, or cognitive difficulties.
BAVI may create difficulties for a person to simultaneously process auditory and visual information and can affect both children and adults.