title: Cross-modal re-organization in adults with early stage hearing loss.
abstract: Cortical cross-modal re-organization, or recruitment of auditory cortical areas for visual processing, has been well-documented in deafness. However, the degree of sensory deprivation necessary to induce such cortical plasticity remains unclear. We recorded visual evoked potentials (VEP) using high-density electroencephalography in nine persons with adult-onset mild-moderate hearing loss and eight normal hearing control subjects. Behavioral auditory performance was quantified using a clinical measure of speech perception-in-noise. Relative to normal hearing controls, adults with hearing loss showed significantly larger P1, N1, and P2 VEP amplitudes, decreased N1 latency, and a novel positive component (P2') following the P2 VEP. Current source density reconstruction of VEPs revealed a shift toward ventral stream processing including activation of auditory temporal cortex in hearing-impaired adults. The hearing loss group showed worse than normal speech perception performance in noise, which was strongly correlated with a decrease in the N1 VEP latency. Overall, our findings provide the first evidence that visual cross-modal re-organization not only begins in the early stages of hearing impairment, but may also be an important factor in determining behavioral outcomes for listeners with hearing loss, a finding which demands further investigation.
authors.affiliation: University of Colorado at Boulder, Department of Speech, Language and Hearing Sciences, Boulder, Colorado, United States of America.
authors.forename: Julia
authors.initials: J
authors.lastname: Campbell
authors.affiliation: University of Colorado at Boulder, Department of Speech, Language and Hearing Sciences, Boulder, Colorado, United States of America ; University of Colorado at Boulder, Institute of Cognitive Science, Boulder, Colorado, United States of America.
authors.forename: Anu
authors.initials: A
authors.lastname: Sharma
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001303:Auditory Cortex / Q000503:physiopathology; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D006309:Hearing; D034381:Hearing Loss / Q000175:diagnosis / Q000503:physiopathology*; D006320:Hearing Tests; D006801:Humans; D008875:Middle Aged; D010775:Photic Stimulation; D013067:Speech Perception / Q000502:physiology*