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Exploring Sensory Deprivation in Deafblindness

Deafblindness is the loss of sight and hearing to the point where your communication, mobility, and ability to access information are impacted. This includes both congenital and ‘progressive’ forms of sensory loss. It is a complex condition which most commonly targets the elderly population; however, it can also affect young children, including babies. According to The National Centre on Deafblindness, many children with deafblindness also live with additional disabilities including cognitive, physical, or behavioural impairments. This article will explore the scientific developments in the field, while also highlighting the personal experiences of individuals living with dual sensory loss.



Cross-modal and Intramodal Plasticity


Villwock & Grin’s article discusses neural reorganisation following sensory deprivation,

particularly auditory loss in deaf and deafblind individuals. It highlights both

cross-modal and intramodal plasticity, as well as the role of language experience in somatosensory processing.


Cross-modal plasticity refers to the brain’s ability to reorganise various neural

pathways to compensate for a deprived sensory region. For example, in congenitally deaf individuals, the absence of auditory input causes the brain to reassign auditory regions to other senses, such as vision or touch. In contrast, intramodal plasticity involves structural changes within existing neural networks, where the brain strengthens and enhances these

networks due to increased demand.


To support this, Allen et al. (2013) found a “larger volume of grey matter in the

primary visual cortex of congenitally deaf individuals” compared to both hearing

signers and non-signers. This illustrates intramodal plasticity, where increased

reliance on vision leads to strengthening and enhanced development of the

visual system itself. Conversely, Lomber et al. (2010) demonstrated cross-modal plasticity in

congenitally deaf cats, who outperformed hearing cats in visual localisation tasks.

This study highlights the recruitment of visual stimuli in auditory regions that are

not typically engaged.


These studies demonstrate the remarkable ways that the brain attempts to compensate for sensory deprivation, particularly in individuals who are deafblind and experience reduced visual and hearing function.



Tactile Processing in Deafblind Individuals


While Villwock & Grin’s article shows that deaf people may rely more on vision as a compensatory response to auditory loss, deafblind individuals don’t have this advantage as they have limited visual input. This places greater emphasis on the somatosensory

system, primarily through touch, as a means of communication and spatial

awareness. However, research shows inconsistencies in tactile processing following sensory deprivation. Heming & Brown (2005) observed that deaf participants had

significantly higher temporal detection thresholds in tactile tasks - nearly four times

higher than those of hearing controls. This indicates reduced sensitivity in distinguishing two touches to their skin as separate events. In these tasks, participants received mechanical stimulation, such as taps on their index and middle fingers of one or both hands, and were asked to determine if the taps occurred simultaneously or not. This is concerning for deafblind individuals as it may affect their ability to process tactile languages, such as Braille, which they depend on heavily. It highlights the need for early tactile training in the deafblind population.



Research Limitations and Challenges


Crucially, the article highlights a significant challenge in the field: the heterogeneity

of participants in sensory deprivation research. Many studies fail to distinguish

between key factors, such as congenital versus late-onset deafness, or early

versus delayed language exposure. This lack of clarity presents a challenge in isolating the actual effects of sensory deprivation, as neural outcomes can also be shaped by language deprivation.


To support this, Villwock & Grin demonstrate that early exposure, and experience of, language shapes somatosensory processing. They found that individuals with delayed access to language exhibited irregular patterns of tactile processing which, ultimately, highlights the role of language experience in determining neurodevelopmental outcomes.



Incorporating Lived Experience into Sensory Deprivation Research


While research provides an objective perspective on the complexity of

deafblindness, personal insights and experiences offer a more comprehensive

outlook that incorporates subjectivity, adding a unique and refreshing aspect.

BBC Radio 4’s In Touch recently devoted an episode to deafblindness, offering

reflections from individuals living with dual sensory loss. Emma Blackmore, a

deafblind individual, uses a “cane going out and about in the community”, which she

describes as tricky since she has to “figure out the best routes” to take. She discusses

the need to find adaptations, which could even be a “simple thing”. Another individual, Jo Milne, lives with Usher Syndrome, which manifests as a form of deafblindness.

She shares how “research is so underfunded” and urges for a conversation around

dual sensory loss within the public domain. Milne presses for more positive representation in the media and strongly advocates for more voices to be heard on the matter. 


In conclusion, while research on deafblindness is growing, there are still evident gaps that need to be addressed - particularly around public awareness, as touched upon in the article. Furthermore, we need to focus on delivering more tailored approaches, as highlighted in BBC Radio 4’s In Touch episode. Individuals like Emma Blackmore and Jo Milne show that deafblindness manifests uniquely. This research made me realise that deafblindness is not a uniform condition and should be recognised as a spectrum of experiences. Raising public awareness is essential to drive progress in both research and representation.



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This article was written by Sriya Sreekantam and edited by Rebecca Pope, with graphics produced by Ginevra Sperandio and Ciara Lee. If you enjoyed this article, be the first to be notified about new posts by signing up to become a WiNUK member (top right of this page)! Interested in writing for WiNUK yourself? Contact us through the blog page and the editors will be in touch.

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