P300 em sujeitos com perda auditiva

Is there a change in P300 evoked potential after 6 months in cochlear implant users?

OBJECTIVE

There are few studies on long-latency auditory evoked potential (P300) in people with hearing loss who use a cochlear implant. Central auditory system evaluation with behavioral and electrophysiological tests is believed to help understand the neuroplasticity mechanisms involved in auditory functioning after cochlear implant surgery. This study investigated the electrophysiological processing of cortical level acoustic signals in a group of 21 adult individuals with postlingual bilateral severe-to-profound hearing loss who were submitted to cochlear implant surgery.

METHODS

Data were collected in three phases: pre-cochlear implant surgery, at cochlear implant activation, and 6 months after surgery. P300 measures were also registered during all phases. Tone-burst and speech stimuli were used to elicit P300 and were presented in free field.

RESULTS

Mean P3 component latency with tone-burst and speech stimuli were 352.9 and 321.9 ms in the pre-cochlear implant phase, 364.9 and 368.7 ms in the activation phase, 336.2 and 343.6 ms 6 months after the surgery. The P3 component mean latency values using tone-burst at activation were significantly different from those 6 months after cochlear implant. They were also significantly different using speech, between pre-cochlear implant and activation phases. Lower P3 component latency occurred 6 months after cochlear implant activation with tone-burst and pre-cochlear implant with speech stimulus. There was a weak correlation between mean P3 component latency with speech stimulus and time of hearing loss. There was no difference in amplitude between phases or in the comparison with the other variables.

CONCLUSION

There were changes in P3 component latency during the period assessed, for both speech and pure-tone stimuli, with increased latency in the activation phase and similar lower results in the two other phases, Pre-CI and 6 months after CI use. Mean amplitude measures did not vary in the three phases.

Cognitive performance and long-latency auditory evoked potentials: a study on aging

OBJECTIVE

To evaluate the relationship between cognitive performance and long-latency auditory evoked potentials in an elderly population.

METHODS

The sample consisted of adults between 20 and 58 years of age and elderly adults between 60 and 70 years of age. The screening procedures adopted were an inspection of the external auditory canal, tonal and vocal audiometry, tympanometry, brain stem auditory evoked potential, the Montreal Cognitive Assessment test, and long-latency auditory evoked potential.

RESULTS

The latency and amplitude values of cortical components by age group showed significant differences under the following conditions: (i) signals evoked by the speech stimulus /da/ and by the pure-tone stimulus at 2,000 Hz for the N2 amplitude (p=0.008 and p=0.001, respectively) , which were both higher for adults, and (ii) signals evoked by the speech stimulus /da/ for N1 latency (p=0.018) and by the pure-tone stimulus at 2,000 Hz for P2 latency (p=0.017), which were both higher in the elderly population. The cognitive component (P300) showed a significant difference when evoked by speech stimuli, with higher latency in the elderly population (p=0.013). When correlated with cognitive processes, the latency and amplitude of cortical potentials showed direct and medium-strength correlations between abnormal scores obtained on the Montreal Cognitive Assessment test and P2 amplitude (p<0.001 and r=0.452).

CONCLUSION

There is a relationship between long-latency potentials and cognitive performance in the elderly, which was observed by the increase in the P2 amplitude and the impairment of the process of sound decoding.

P300 Event-Related Potentials in Normal-Hearing Adults With Type 2 Diabetes Mellitus

Background P300 event-related potentials can be used to measure auditory processing speed, working memory, and attention. Purpose The purpose of the study was to compare P300 event-related potentials in normal-hearing adults with those of adults with Type II diabetes mellitus. Research Design A two-group (with diabetes and controls) comparative study (age- and sex-matched) with a nonprobability sampling method was used. Study Sample Sixty-four adult participants (32 with diabetes, 32 without diabetes) between the ages of 23 and 60 years participated. Data Collection and Analysis Pure-tone audiometry was performed to ensure participants had pure-tone averages of ≤ 25 dB HL. Folstein Mini-Mental State Examinations were conducted, which ensured absence of cognitive impairment. Blood glucose levels were measured immediately prior to P300 testing, after which amplitude and latency results were captured. Descriptive analysis was used to calculate mean, standard deviation, median, and 25th and 75th percentiles. To study differences between adults with and without diabetes as well as the effect of glucose, linear mixed-model regression analyses were performed when left and right ears were combined, and simple linear regression analyses were performed when left and right ears were analyzed separately. Results For P300 latency results, a significant statistical difference (p < .001) was observed between participants with and without diabetes (352.46 ms, SD = 36.36; 314.09 ms, SD = 32.08), respectively. A significant statistical difference (p < .001) in amplitude was observed between participants with and without diabetes, respectively (12.10 μV, SD = 3.70; 15.08 μV, SD = 2.82). Glucose was a key moderator of only amplitude after adjusting for diabetes status. Glucose had no effect on amplitude and latency for adults without Type II diabetes mellitus (DM). Conclusions Type II DM decreases amplitude and increases latency; in addition, adults with Type II DM, attention, and working memory, as denoted by P300 amplitude, may deteriorate with increased glucose levels on the day of testing.

Monitoring auditory cortical plasticity in hearing aid users with long latency auditory evoked potentials: a longitudinal study

OBJECTIVE

The objective of this study was to compare long-latency auditory evoked potentials before and after hearing aid fittings in children with sensorineural hearing loss compared with age-matched children with normal hearing.

METHODS

Thirty-two subjects of both genders aged 7 to 12 years participated in this study and were divided into two groups as follows: 14 children with normal hearing were assigned to the control group (mean age 9 years and 8 months), and 18 children with mild to moderate symmetrical bilateral sensorineural hearing loss were assigned to the study group (mean age 9 years and 2 months). The children underwent tympanometry, pure tone and speech audiometry and long-latency auditory evoked potential testing with speech and tone burst stimuli. The groups were assessed at three time points.

RESULTS

The study group had a lower percentage of positive responses, lower P1-N1 and P2-N2 amplitudes (speech and tone burst), and increased latencies for the P1 and P300 components following the tone burst stimuli. They also showed improvements in long-latency auditory evoked potentials (with regard to both the amplitude and presence of responses) after hearing aid use.

CONCLUSIONS

Alterations in the central auditory pathways can be identified using P1-N1 and P2-N2 amplitude components, and the presence of these components increases after a short period of auditory stimulation (hearing aid use). These findings emphasize the importance of using these amplitude components to monitor the neuroplasticity of the central auditory nervous system in hearing aid users.

Auditory Evoked Potentials with Different Speech Stimuli: a Comparison and Standardization of Values

Introduction Long Latency Auditory Evoked Potentials (LLAEP) with speech sounds has been the subject of research, as these stimuli would be ideal to check individualś detection and discrimination.

Objective The objective of this study is to compare and describe the values of latency and amplitude of cortical potentials for speech stimuli in adults with normal hearing.

Methods The sample population included 30 normal hearing individuals aged between 18 and 32 years old with ontological disease and auditory processing. All participants underwent LLAEP search using pairs of speech stimuli (/ba/ x /ga/, /ba/ x /da/, and /ba/ x /di/. The authors studied the LLAEP using binaural stimuli at an intensity of 75dBNPS. In total, they used 300 stimuli were used (∼60 rare and 240 frequent) to obtain the LLAEP. Individuals received guidance to count the rare stimuli. The authors analyzed latencies of potential P1, N1, P2, N2, and P300, as well as the ampleness of P300.

Results The mean age of the group was approximately 23 years. The averages of cortical potentials vary according to different speech stimuli. The N2 latency was greater for /ba/ x /di/ and P300 latency was greater for /ba/ x /ga/. Considering the overall average amplitude, it ranged from 5.35 and 7.35uV for different speech stimuli.

Conclusion It was possible to obtain the values of latency and amplitude for different speech stimuli. Furthermore, the N2 component showed higher latency with the / ba / x / di / stimulus and P300 for /ba/ x / ga /.

Auditory evoked potential P300 in adults: reference values

OBJECTIVE

To establish reference intervals for cognitive potential P300 latency using tone burst stimuli.

METHODS

This study involved 28 participants aged between 18 and 59 years. P300 recordings were performed using a two-channel device (Masbe, Contronic). Electrode placement was as follows: Fpz (ground electrode), Cz (active electrode), M1 and M2 (reference electrodes). Intensity corresponded to 80 dB HL and frequent and rare stimulus frequencies to 1,000Hz and 2,000Hz, respectively. Stimuli were delivered binaurally.

RESULTS

Mean age of participants was 35 years. Average P300 latency was 305ms.

CONCLUSION

Maximum acceptable P300 latency values of 362.5ms (305 + 2SD 28.75) were determined for adults aged 18 to 59 years using the protocol described.

OBJETIVO

Estabelecer valores de referência para a latência do potencial cognitivo P300 com estímulos tone burst.

MÉTODOS

Participaram do estudo 28 indivíduos entre 18 e 59 anos. O registro do P300 foi realizado no equipamento Masbe da marca Contronic. Os eletrodos foram fixados nas posições Fpz (eletrodo terra), Cz (eletrodo ativo), M1 e M2 (eletrodos referência). A intensidade foi de 80 dB NA. A frequência do estímulo frequente foi de 1.000Hz e a do estímulo raro de 2.000Hz. Os estímulos foram apresentados na forma binaural.

RESULTADOS

A média de idade dos indivíduos foi de 35 anos. A média de latência para P300 de 305ms.

CONCLUSÃO

Usando o protocolo descrito, o valor máximo de latência aceitáveis para P300 foram de 362,5ms (305 + 2DP 28,75) na faixa etária do adulto de 18 a 59 anos.

Potencial evocado auditivo de longa latência: diferenças na forma de contagem do estímulo raro

RESUMO Objetivo: identificar se existe diferença nos achados do Potencial Evocado Auditivo de Longa Latência em relação à latência e amplitude, em diferentes modos de contagem do estimulo raro, sendo contando mentalmente ou marcando no papel (sem memorizar). Métodos: esse estudo teve caráter prospectivo e transversal. A amostra foi composta por conveniência sendo constituída por 49 indivíduos, sendo 29 do gênero feminino e 20 do gênero masculino. Foram realizados os seguintes procedimentos: Inspeção Visual do Meato Acústico Externo, Audiometria Tonal Liminar, Medidas de Imitância Acústica e Potencial Evocado Auditivo de Longa Latência, o qual foi realizado duas vezes, uma após a outra, com os indivíduos atentando ao estímulo raro, começando sempre contando mentalmente e após marcando em um papel. Resultados: houve diferença estatisticamente significante entre as orelhas para as latências de P1, P2 e amplitude de N1 para o método de marcação no papel, da latência de N1 para o método de contagem mental dos estímulos raros, e da amplitude de P2 em ambos os métodos, porém com todos os valores dentro da faixa de normalidade. Além disso, a diferença estatisticamente significante também foi evidente na comparação entre os gêneros, sendo encontrados valores de latência maiores de P2 e N2 para o gênero masculino em ambos os métodos de contagem dos estímulos raros. A amplitude de P1, P2 e P3 foi menor no gênero masculino nas diferentes formas de contagem, sendo no P2 a diferença apenas no método contando mentalmente. Ao compararmos os métodos, houve diferença estatisticamente significante apenas para a latência de P2, a qual foi maior para o método marcando no papel. Conclusão: não houve diferença para as latências e amplitudes dos potenciais evocados auditivos de longa latência na comparação da contagem do estímulo raro (contando mentalmente e marcando no papel) para quase todos os potenciais, com exceção do potencial P2 em relação à latência e amplitude.

The influence of speech stimuli contrast in cortical auditory evoked potentials

Objective

Method

Results

Conclusion

Correlation of the P300 evoked potential in depressive and cognitive aspects of aging

The P300 is a long-latency auditory evoked potential highly dependent on cognitive skills. It is believed that cognitive changes caused or not by depressive symptoms may interfere with the P300.

AIM

To investigate the influence of aging, cognitive and depression aspects of the P300 latency in elderly people.

METHODS

Clinical and experimental study with 60 elderly patients with sensorineural hearing loss of mild to moderately severe level, 20 males and 40 females, average age of 71.1. Participants were submitted to the long latency auditory evoked potential, in which the P300 latency (milliseconds) was studied. The cognitive aspects were assessed using the Mini-Mental State Examination (MMSE) and Alzheimer's Disease Assessment Scale (ADAS-Cog). In the assessment of depressive symptoms the Geriatric Depression Scale (GDS-15) was applied.

RESULTS

We found a significant positive correlation between latency and age (p = 0.031). There were no significant differences among the P300 latency and the ADAS-Cog (p = 0.584), MMSE (p = 0.199) and GDS (p = 0.541) categories.

CONCLUSION

Aging caused an increase in the P300 latency; however, cognitive performance and the presence of depressive symptoms did not influence the P300 results in this elderly population.

Cognição e eletrofisiologia: uma revisão crítica das perspectivas nacionais

A técnica eletrofisiológica Potenciais Relacionados ao Evento (PRE) vem sendo amplamente utilizada para o estudo da atividade cerebral correspondente a processos cognitivos específicos. O presente artigo apresenta uma revisão crítica dos estudos empregando PRE desenvolvidos em universidades brasileiras, enfatizando especialmente seus objetivos principais e abordagens metodológicas. Os estudos examinados investigaram efeitos eletrofisiológicos tradicionalmente reportados na literatura em PRE, como os efeitos denominados P300, N400 e MMN, proporcionando resultados relevantes teoricamente, bem como demonstrando a utilidade do PRE para a investigação de diversos temas de pesquisa. Possibilidades referentes a abordagens metodológicas alternativas para a análise dos PREs, assim como o emprego desta técnica no estudo de diversos processos psicológicos, são examinados e discutidos.

Mismatch Negativity (MMN) response studies in elderly subjects

Mismatch Negativity is an endogenous potential which reflects the processing of differences incurred in the acoustic stimulus.

AIM

to characterize MMN responses in elderly subjects and compare with adult subjects.

MATERIALS AND METHODS

prospective study involving 30 subjects, 15 men and 15 women, aged between 60 and 80 years and 11 months. Statistical test: Mann-Whitney. The subjects went through medical evaluation, threshold tonal audiometry, immittance tests, otoacoustic emissions and short and long latency auditory potentials (MMN).

RESULTS

mean latency was 161.33 ms (CZA2) and 148.67 ms (CZA1), in women; of 171 ms (CZA2) and 159.07 ms (CZA1), men. Mean amplitude was -2.753 microV (CZA2) and -2.177 microV (CZA1), women; -1.847 microV (CZA2) and -1.953 microV (CZA1), men. As to the right and left hemispheres, mean latency variable of 166 ms (CZA2) and 153.87 ms (CZA1); for the amplitude variable, mean value of -2.316 microV (CZA2) and -2.065 microV (CZA1).

CONCLUSION

there is no statistically significant difference between the latency and amplitude when we compared males and females, right and left sides in the elderly and between chronologic ages between adults and elderly subjects.