Η αντιληπτική λειτουργία παιδιών 8-13 ετών με προγλωσσική απώλεια ακοής

In this study, we investigated the perceptual function of deaf/hard of hearing children. The sample of the study consisted of 58 pupils aged 8-13 years old (3rd-6th graders) with severe (60-90 db) or profound (90 db and above) neurosensory hearing loss – pre-lingual with or without cochlear implants. Children with co-morbidity (intellectual disabilities, syndromes, autism, motor disorders, etc.) and children with post-lingual deafness/hearing impairment were excluded. In order to investigate their perceptual function, the Perceptual Functionality Criterion was used. The results of the study show that deaf/hard of hearing participants exhibit a “sporadic” profile regarding the general perceptual functionality. In particular, the participants were found to perform similarly in terms of visual-perceptive skills, while there was one exception, i.e. their visual-motor skills were worse. Higher scores have been shown in the domain of kinesthetic and tactile perception and lower ones regarding vestigial perception, especially in terms of the sense of balance. In addition, the perceptual function was investigated among the cochlear implant participants and those with conventional hearing aids. The results showed no significant differences between the two groups regarding the perceptual function, although the visual perception was found to be significantly better among the users of conventional hearing aids relative to cochlear implant users. Finally, the perceptual function was investigated in terms of the main method of language/communication used. The data indicated that participants, regardless of whether they use sign language, total/bilingual or oral communication, performed roughly similarly on the test variables. Among the different types of main method of language/communication, statistically significant differences were absent, though regarding the visual and kinesthetic perception sign language users outperformed the users of oral communication.

Tactile perception by mouth: Perceiving properties of objects when vision is impaired

The lips and tongue demonstrate similar or greater spatial acuity than the fingertips. Indeed, infants use the mouth to perceive properties of objects such as hardness, texture, and shape. In normal development, it is assumed that mouthing decreases in favour of increasingly advanced hand exploration patterns. However, anecdotal reports suggest that mouthing continues to serve a perceptual function when a person’s vision is abnormal. This study explored blind or visually impaired (BVI) adults’ self-reported use of mouthing to perceive properties of objects. We conducted semi-structured interviews with 20 BVI adults with visual acuities ranging from no light perception to 20/40. Data were analysed using content analysis to identify specific properties perceived by the mouth. Despite social norms that discourage mouthing, some BVI adults use oral tactile perception of texture, shape, temperature, and taste to better characterize objects. These findings suggest that compensatory behaviours using the mouth can support the rehabilitation of individuals with abnormal vision.

Higher-order thalamic implication in the processing of bilateral sensory events

In the rodent whisker system, it is well assumed that VPM and POm encode stimulations of the contralateral whisker pad. However, during tactile exploration whiskers are usually stimulated bilaterally. Accordingly, the integration of tactile information from the two sides of the body seems to be fundamental in the processing of these events. Here, to investigate whether POm could be able to codify these bilateral dynamics, whisker-evoked responses in this thalamic nucleus were examined by in vivo extracellular recordings in anesthetized rats using contralateral and ipsilateral stimuli. Strikingly, we found that POm is also able to respond to tactile stimulation of ipsilateral whiskers. Our findings reveal the implication of POm in the representation of bilateral tactile events by integrating simultaneous signals arising from both whisker pads and demonstrate the implication of the higher-order sensory thalamus in the encoding of bilateral sensory events. This can have important implications in bilateral perceptual function.