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.

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

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.

Relationship Between Patients with Clinical Auditory Neuropathy Spectrum Disorder and Mutations in Gjb2 Gene.

The auditory neuropathy is a condition which there is a dyssynchrony in the nerve conduction of the auditory nerve fibers. There is no evidence about the relationship between patients with clinical auditory neuropathy spectrum disorder and mutations in GJB2 gene. There are only two studies about this topic in the medical literature. Connexin 26 (GJB2 gene) mutations are common causes of genetic deafness in many populations and we also being reported in subjects with auditory neuropathy. OBJECTIVE: To analyze the pattern of clinical relationship between patients with clinical diagnosis with auditory neuropathy spectrum disorder and GJB2 gene. PATIENTS AND METHODS: Study Design - Retrospective analysis and genetic evaluation. Setting - Tertiary referral center. Subjects - 40 patients with Auditory Neuropathy Spectrum Disorder. Intervention - Clinical information and genetic evaluation (GJB2 gene) were analyzed. RESULTS: Biallelic mutations that accounted for hearing loss (HL) were found in three patients, both with c.35delG mutation in homozygous state. The splice site mutation IVS1+1G>A was detected in heterozygous state in one individual. However, since the second mutant allele was not identified, it was not possible to establish its correlation with the phenotype. CONCLUSION: Mutations in GJB2 gene mutations were found in 7.5% of the patients with ANSD. We found no relationship between patients with clinical auditory neuropathy spectrum disorder and mutations in GJB2 gene (p>0.05).

Estudio electrofisiológico y electroacústico de un desorden del espectro de neuropatía auditiva: reporte de un caso en recién nacido de alto riesgo / Electrophysiology and electroacoustic study of spectrum disorder of auditory neuropathy: report of a case in high-risk newborn

El desorden del espectro de neuropatía auditiva (DENA) describe una condición en la cual se observa o se ha observado emisiones otoacústicas (EOA) junto con potenciales evocados auditivos de tronco (PEAT) anormales o ausentes. Su identificación se basa en la presencia de potencial microfónico coclear (PMIC) junto con un PEAT anormal o ausente y EOA presentes o antecedentes de su presencia. Los umbrales tonales pueden encontrarse entre los rangos de normalidad hasta pérdidas auditivas profundas. El reconocimiento del habla generalmente se encuentra afectado particularmente en presencia de ruido de fondo, sin embargo en algunos individuos se mantiene conservado (sin ruido). Se presenta caso clínico de un recién nacido de sexo femenino de pretérmino de 29 semanas y 810 grs (GIII), apgar 7/8, presenta displasia broncopulmonar, sospecha de infección connatal tratada, hiperbilirrubinemia (max 11 mg/dl) tratada con fototerapia. Es derivada al Servicio de Otorrinolaringología para su evaluación auditiva. La evaluación auditiva realizada corresponde a potenciales evocados auditivos de tronco (PEAT), impedanciometria, audiometría de campo de respuesta reflejas y emisiones oto-acústicas. Los resultados obtenidos concuerdan con lo descrito en la literatura para un DENA.

Auditory neuropathy spectrum disorder (ANSD) describes a condition in which it is possible to find otoacoustic emissions (OAE) in presence of abnormal or absent auditory brainstem evoked potentials (ABR). The pure tone thresholds may show a spectrum from normal to profound hearing loss. Speech recognition is often affected in presence of background noise, but in some individuals remains intact. We report a case of a pre term newborn (female) of 29 weeks and 810 grams, Apgar 7/8, bronchopulmonary dysplasia, suspected connatal infection, and hyperbilirubinemia (max 11 mg / dl). She was referred to Hospital Padre Hurtado for hearing assessment. The hearing test performed were an ABR, tympanometry & acoustic reflex, visual reinforcement audiometry and otoacoustic emissions. The results are consistent with those described in the literature for ANSD.