Effect of Quiet and Noise on P300 Response in Individuals with Auditory Neuropathy Spectrum Disorder

Abstract Introduction Auditory neuropathy spectrum disorder (ANSD) is a clinical condition in which individuals have normal cochlear responses and abnormal neural responses. There is a lack of evidence in the literature regarding the neural discrimination skill in individuals with ANSD, especially when the signal is presented in the presence of noise. Objectives The present study was performed with the aim to investigate auditory discrimination skill, in quiet and in the presence of noise, in individuals with ANSD and to compare the findings with normal-hearing individuals. Methods A total of 30 individuals with normal hearing sensitivity and 30 individuals with ANSD in the age range of 15 to 55 years old, with the mean age of 27.86 years old, were the participants. P300 response was recorded from both groups using syllable pairs /ba/-/da/ in oddball paradigm and the syllable /da/ in repetitive paradigm in quiet and at +10 dB signal-to-noise ratio (SNR). Results There was significant prolongation in latency and reaction time, and reduction in amplitude of P300 response and sensitivity in both groups with the addition of noise. The topographic pattern analysis showed activation of the central-parietal-occipital region of the brain in individuals with ANSD, whereas activation of the central-parietal region was observed in individuals with normal hearing. The activation was more diffused in individuals with ANSD compared with that of individuals with normal hearing. Conclusion The individuals with ANSD showed a significantly more adverse effect of noise on the neural discrimination skill than the normal counterpart.

Cortical Auditory Evoked Potential: evaluation of speech detection in adult hearing aid users / Potencial Evocado Auditivo Cortical: avaliação da detecção de fala em adultos usuários de prótese auditiva

Purpose: To analyze the presence of auditory cortical potential and its correlation with psychoacoustic detection of speech sounds as well as the latency of the P1, N1 e P2 components presented in free field in hearing impaired adults with and without amplification. Methods: We evaluated 22 adults with moderate to severe symmetrical bilateral sensorineural hearing loss, regular users of bilateral hearing aids. Speech sounds of low (/m/), medium (/g/) and high (/t/) frequencies were presented in sound field in decreasing intensities of 75, 65 and of 55 dBSPL in free field with and without hearing aids. The used equipment performs automatic statistical detection of the presence of response; forthermore, the latencies of waves P1, N1 e P2 were labeled and the psychoacoustic perception was registered. Results: The results demonstrated the increased presence of cortical response with hearing aids. We observed the correlation between psychoacoustic perception and automatic detection of 91% for the sounds /g/ and /t/ and ranged from 73 to 86% for the sound /m/. The averages of latencies P1-P2-N1 decreased with both increasing intensity and the use of hearing aids for the three sounds. The differences were significant for the sounds /g/ and /t/ in comparison with and without hearing aids. Conclusion: There was increase in the presence of cortical auditory evoked potential with hearing aids. Automatic detection of cortical response provided with hearing aids showed 91% agreement with the psychoacoustic perception of the speech signal. In the analysis of latency measures of the P1, N1 and P2 components, it was observed a decrease with the increase of the signal intensity and the use of amplification for the three speech stimuli /m/, /g/ and /t/.

Objetivo: Analisar a presença do potencial auditivo cortical e sua concordância com a detecção psicoacústica de sons de fala bem como a latência dos componentes P1, N1 e P2 apresentados em campo livre em adultos deficientes auditivos com e sem o uso da amplificação. Métodos: Foram avaliados 22 adultos com perda auditiva sensorioneural bilateral simétrica de grau moderado a severo, usuários regulares de prótese auditiva bilateral. Foram utilizados estímulos de fala de baixas (/m/), médias (/g/) e altas (/t/) frequências, apresentados em intensidades decrescentes de 75, 65 e 55 dBNPS em campo livre nas condições sem e com o uso de próteses auditivas. O equipamento utilizado realiza a detecção estatística automática da resposta; além disso, as latências das ondas P1, N1 e P2 foram marcadas e a percepção psicoacústica foi registrada. Resultados: Os resultados demonstraram o aumento da presença de resposta cortical na condição com prótese auditiva. Observou-se a concordância entre a percepção psicoacústica e a detecção automática de 91% para os sons /g/ e /t/ e variou de 73 a 86% para o som /m/. As médias das latências P1, N1 e P2 diminuíram tanto com o aumento da intensidade como com o uso da prótese auditiva para os três sons de fala. As diferenças foram significantes para os sons /g/ e /t/ na comparação sem e com prótese auditiva. Conclusão: Houve aumento da presença do potencial evocado auditivo cortical na condição com prótese auditiva. A detecção automática da presença de resposta cortical na condição com prótese auditiva apresentou 91% de concordância com a percepção psicoacústica do sinal de fala. Na análise das medidas de latência dos componentes P1, N1 e P2, observou-se a uma diminuição tanto com o aumento da intensidade do sinal como com o uso da amplificação para os três estímulos de fala /m/, /g/ e /t/.

Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics

The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5° × 5°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP and both psychophysical contrast sensitivity functions (CSFs) were low-pass functions for red-green gratings. For electrophysiology, the highest contrast sensitivity values were found at 0.4 cpd (1.95 ± 0.15). ssVECP CSF was similar to dynamic psychophysical CSF, while static CSF had higher values ranging from 0.4 to 6 cpd (P < 0.05, ANOVA). Blue-yellow chromatic functions showed no specific tuning shape; however, at high spatial frequencies the evoked potentials showed higher contrast sensitivity than the psychophysical methods (P < 0.05, ANOVA). Evoked potentials can be used reliably to evaluate chromatic red-green CSFs in agreement with psychophysical thresholds, mainly if the same temporal properties are applied to the stimulus. For blue-yellow CSF, correlation between electrophysiology and psychophysics was poor at high spatial frequency, possibly due to a greater effect of chromatic aberration on this kind of stimulus.

Research progress of brain-computer interface technology / 国际生物医学工程杂志

Brain computer interface (BCI) is an interactive communication technology which can be achieved independent of human peripheral nerves and muscles.It provides a man-machine communication and control channel,without using muscular tissue,and makes the communication with outside world possible.This review describes the composition and working principle of the BCI system on the basis of the pervious research results.Then,it focuses on the comparative analysis of physiological parameter and the methods of feature extraction of visual evoked potential technology,spontaneous MU rhythm technology,slow cortical potential technology and so on.At last,the application of BCI technology and the prospect of its development are summarized.

Comparison of the reliability of multifocal visual evoked cortical potentials generated by pattern reversal and pattern pulse stimulation

This study compared the effectiveness of the multifocal visual evoked cortical potentials (mfVEP) elicited by pattern pulse stimulation with that of pattern reversal in producing reliable responses (signal-to-noise ratio >1.359). Participants were 14 healthy subjects. Visual stimulation was obtained using a 60-sector dartboard display consisting of 6 concentric rings presented in either pulse or reversal mode. Each sector, consisting of 16 checks at 99% Michelson contrast and 80 cd/m² mean luminance, was controlled by a binary m-sequence in the time domain. The signal-to-noise ratio was generally larger in the pattern reversal than in the pattern pulse mode. The number of reliable responses was similar in the central sectors for the two stimulation modes. At the periphery, pattern reversal showed a larger number of reliable responses. Pattern pulse stimuli performed similarly to pattern reversal stimuli to generate reliable waveforms in R1 and R2. The advantage of using both protocols to study mfVEP responses is their complementarity: in some patients, reliable waveforms in specific sectors may be obtained with only one of the two methods. The joint analysis of pattern reversal and pattern pulse stimuli increased the rate of reliability for central sectors by 7.14% in R1, 5.35% in R2, 4.76% in R3, 3.57% in R4, 2.97% in R5, and 1.78% in R6. From R1 to R4 the reliability to generate mfVEPs was above 70% when using both protocols. Thus, for a very high reliability and thorough examination of visual performance, it is recommended to use both stimulation protocols.

Short-term Modulation of Scalp Acupuncture on Cortical Excitability and Motor-related Cortical Potential / 世界科学技术-中医药现代化

This study was aimed to investigate short-term modulation mechanism of scalp acupuncture according to the experimentation of cortical excitability and motor-related cortical potentials in ten normal volunteers.Through scalp needle stimulation in specific theoretical areas related to underlying cerebral surfaces,scalp acupuncture can be used as an effective therapy by changes in relative cerebral function,which is the basic principle.According to the available neurophysiological data in our study,the modulation of scalp acupuncture displayed in late part of motor-related cortical potential noticed mainly in the motor and sensory cortexes,contralateral to the needle stimulate site.Also,acupuncture can develop inhibition at longer interstimulus intervals,in paired pulse magnetic stimulation,from the somatosensory input of contralateral sensory cortex via scalp needle stimulation.In our study,it might be difficult to produce more acupuncture inhibition.The maintaining of scalp needles subcutaneously without other management after achieving needling sensations cannot achieve the requested strength of the acupuncture stimulation.

Efficacy of Methylprednisolone in Aconite Induced Myelo-optic Neuropathy in the Rabbit

Studies in animals indicate that aconitine or aconite has toxic effects in the visual system of a rabbit model. Such a toxic effects causes myelo-optic neuropathy in the visually evoked cortical potential(VECP) and histopathologic studies. Whether the administration of intravenous high-dose of methyprednisolone(MP) in the myelo-optic neuropathy caused by aconitine(1.5ml/kg, equivalent to 0.7mg/kg of aconitine) is experimentally effective remains uncertain. The group treated with MP(daily 30mg/kg X 2 for 3 days followed by 15mg/kg for 3 days) in addition to aconite was compared with the aconite alone group and the normal control group. In the MP treated group, increased recovery of onset latency, peak latency, and amplitude in VECP in comparision with the aconite alone group was recorded at 2 weeks (p<0.05). The MP treated group in comparision with the normal control group showed a significant delay in onset latency at 1 month and 2 months(p<0.05). But, the amplitude in both the MP treated group and the aconite alone group increased at 2 months and did not show a significant difference in comparision with the normal group(p<0.05). In histopathologic study, pathologic findings of myelin sheath in the MP treated group were less severe than in the aconite alone group generally. The true benefit of high-dose MP was at least clear within 2 weeks. The authors conclude that treatment with intravenous high-dose MP immediate after aconite injection may have some beneficial effects in recovery of neurologic function although such a treatment do not have the definite recovery in aconite induced myelo-optic neuropathy.