Full text
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| Author(s): |
Marcos Roberto Banhara
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD) |
| Defense date: | 2007-03-13 |
| Examining board members: |
Orozimbo Alves Costa Filho;
Carlos Alberto Herrerias de Campos
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| Advisor: | Orozimbo Alves Costa Filho |
| Abstract | |
Introduction: Cochlear implants supply subjects presented with severe and profound hearing loss, who do not benefit from the hearing aid, with a greater communication ability. The long latency auditory evoked potentials (N1, P2, N2 and P300) are a differential indicator in the assessment of cochlear implant users. These potentials provide objective parameters of neural generators related to the skills of attention, discrimination and memorization of tonal or speech stimuli. In this study, potentials N1, P2, N2 and P300, generated through speech stimuli in cochlear implant users, were characterized and correlated with the variables speech perception, time of deafness and time of cochlear implant use. Methodology: the research was carried out at the Speech Pathology clinic of the Dental School and at the Audiological Research Center with the Craniofacial Anomalies Rehabilitation Hospital, both with University of São Paulo at Bauru, SP. The potentials were recorded by electrodes placed in regions Cz/Fz/M1/M2 of the skull and connected to the Biologic\'s Evoked Potential System (EP) through cables, according to the standards of international system 10-20. Twenty-five cochlear implant users, presented with pre-lingual deafness, in the age range 6.6 - 12.3 yrs, participated in the study. The subjects were requested to raise their hand as soon as they heard the rare stimulus (/a/ and /da/), presented in the proportion 20/80 in relation to the frequent stimulus (/i/ and /ba/). The speech stimuli /ba-da/ and /i-a/ were presented in oddball paradigm, at an intensity of 60 dB NPS, through a speaker. Results: statistically significant correlations were observed between the latency of potential N1 and the time of deafness and time of cochlear implant use; between amplitude of potential P2 and the time of deafness and time of cochlear implant; between the latency of potential P300 and word recognition. The mean latency of N1 increased 6 ms per year in relation to the time of deafness, with the time of implant use constant and diminished 3 ms according to the increase of 1 year in the time of use. The mean amplitude of P2 diminished 1 ?V, as the time of deafness increased in a year, by keeping fixed the time of use, and increased 0.5 ?V, with the increase of a year in the time of CI use, by keeping constant the time of deafness. The mean latency of potential P300 increased 2 ms as the word recognition score worsened and diminished 2 ms proportionally to the improvement of the same score. Conclusions: The variables time of deafness and cochlear implant use influenced the latency and amplitude of potentials N1 and P2, suggesting a cortical plasticity. The latency of potential P300 reflected the cognitive processes related to skills of auditory attention and discrimination, and presented a significance relation with the word perception score, in the subjects evaluated (AU) | |
| FAPESP's process: | 05/03613-7 - Cognitive Potential - P300 evoked by speech stimulation in multichannel cochlear implant users |
| Grantee: | Marcos Roberto Banhara |
| Support Opportunities: | Scholarships in Brazil - Master |