Detección de novedad y codificación predictiva en el sistema auditivo: Impacto clínico en disfunciones auditivas y vestibulares. Revisión de la literatura

Una propiedad fundamental de los sistemas sensoriales es su capacidad para detectar estímulos novedosos en el entorno. El sistema nervioso posee neuronas que disminuyen su respuesta a los estímulos sonoros que se repiten a lo largo del tiempo y otras neuronas que aumentan su frecuencia de disparo ante estímulos novedosos, siendo la diferencia entre ambas respuestas conocida como adaptación-específica a estímulos. En las últimas décadas, se ha propuesto que el cerebro establece, continuamente, predicciones de los estímulos novedosos y del entorno basándose en sus experiencias previas y en modelos de representación internos, teoría denominada codificación predictiva. En esta revisión, abordaremos algunos conceptos de la adaptación-específica a estímulos y codificación predictiva, centrándonos principalmente en el sistema auditivo. Por último, propondremos una explicación teórica basada en el marco de la codificación predictiva para algunas disfunciones neuropsiquiátricas, auditivas y vestibulares.

A fundamental property of sensory systems is their ability to detect novel stimuli in the environment. The nervous system possesses neurons that decrease their response to sound stimuli that are repeated over time and other neurons that increase their firing rate to novel stimuli, the difference between the two responses being known as stimulus-specific adaptation. In recent decades, it has been proposed that the brain continuously makes predictions of novel stimuli and the environment based on its previous experiences and internal representational models, a theory called predictive coding. In this review, we will address some concepts of stimulus-specific adaptation and predictive coding, focusing mainly on the auditory system. Finally, we will propose a theoretical explanation based on the predictive coding framework for some neuropsychiatric, auditory, and vestibular dysfunctions.

Potencial de disparidad o Mismatch negativity y P3a en pacientes con esquizofrenia / Mismatch negativity and P3a in patients with Schizophrenia

Resumen Antecedentes: la esquizofrenia es una enfermedad crónica que genera gran discapacidad, para la cual se han reportado biomarcadores potenciales, pero sin suficiente validez clínica. El mismatch negativity (MMN) y el P3a son potenciales relacionados con eventos que han demostrado ser indicadores neurofisiológicos del procesamiento auditivo pre-atencional y potenciales biomarcadores. Objetivo: evaluar el MMN y P3a en pacientes con diagnóstico de esquizofrenia y su relación con variables sociodemográficas y clínicas. Método: estudio cuantitativo transversal de 23 sujetos con esquizofrenia (ESQ) y 22 controles sanos (SN). Las amplitudes promedio y latencias del MMN/P3a para la condición infrecuente en duración y frecuencia fueron obtenidas mediante un paradigma oddball auditivo en un EEG de 32 canales. Resultados: se encontraron diferencias para la condición frecuencia en la amplitud del MMN (p=0.046; CI 95% 0.009; 0.87) y la amplitud del P3a (p=0.042; CI 95% 0.025; 1.24) entre los grupos; la amplitud del MMN fue menor en el grupo ESQ (-0.36 DE 0.51 µV) en comparación con los participantes del grupo de SN (-0.81 DE 0.89 µV), mientras que la amplitud del P3a fue menor en el grupo SN (0.18 DE 0.97 µV) versus el grupo ESQ (0.82 DE 1.05 µV). En relación con las variables sociodemográficas y clínicas, las asociaciones con el P3a fueron moderadas y con el MMN débiles. Conclusiones: la reducción de la amplitud del MMN a la condición frecuencia exhibe mayor utilidad que el P3a como medida de alta estabilidad en pacientes con esquizofrenia, lo que reitera su posible uso como biomarcador.

Abstract Background: schizophrenia is a chronic disease that generates great disability, which currently has potential biomarkers but without sufficient clinical validity. Mismatch negativity (MMN) and P3a are event-related potentials that have been shown to be neurophysiological indicators of pre-attentional auditory processing and potential biomarkers. Objective: to evaluate MMN and P3a in patients with a diagnosis of schizophrenia and their relationship with sociodemographic and clinical variables. Method: a quantitative cross-sectional study of 23 subjects with schizophrenia and 22 healthy controls was performed. The average amplitudes and latencies of the MMN/P3a for the condition infrequent in duration and infrequent in frequency were obtained using an auditory oddball paradigm on a 32-channel EEG. Results: differences were found for the frequency condition in the amplitude of the MMN (p=0.046; 95% CI 0.009; 0.87) and the amplitude of the P3a (p=0.042; 95% CI 0.025; 1.24) between the groups; MMN amplitude was lower in schizophrenia (-0.36 SD 0.51 µV) compared to healthy controls (-0.81 SD 0.89 µV), while P3a amplitude was lower in healthy controls (0.18 SD 0.97 µV) versus the group with schizophrenia (0.82 SD 1.05 µV). In regard to sociodemographic and clinical variables, the associations with P3a were moderate, and showed weak MMN. Conclusions: MMN amplitude reduction to the frequency condition exhibits greater utility than P3a as a measure of high stability in schizophrenia, restating its potential use as a biomarker.

Does mismatch negativity have utility for NMDA receptor drug development in depression?

Rapid antidepressant effects associated with ketamine have shifted the landscape for the development of therapeutics to treat major depressive disorder (MDD) from a monoaminergic to glutamatergic model. Treatment with ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, may be effective, but has many non-glutamatergic targets, and clinical and logistical problems are potential challenges. These factors underscore the importance of manipulations of binding mechanics to produce antidepressant effects without concomitant clinical side effects. This will require identification of efficient biomarkers to monitor target engagement. The mismatch negativity (MMN) is a widely used electrophysiological signature linked to the activity of NMDA receptors (NMDAR) in humans and animals and validated in pre-clinical and clinical studies of ketamine. In this review, we explore the flexibility of the MMN and its capabilities for reliable use in drug development for NMDAR antagonists in MDD. We supplement this with findings from our own research with three distinct NMDAR antagonists. The research described illustrates that there are important distinctions between the mechanisms of NMDAR antagonism, which are further crystallized when considering the paradigm used to study the MMN. We conclude that the lack of standardized methodology currently prevents MMN from being ready for common use in drug discovery. Clinical trial registration: This manuscript describes data collected from the following National Institutes of Health (NIH) and Veterans Affairs (VA) studies: AV-101, NCT03583554; lanicemine, NCT03166501; ketamine, NCT02556606.

Research and Prospect of Visual Event-Related Potential in Traumatic Brain Injury and Visual Function Evaluation / 法医学杂志

Visual event-related potential (ERP) is an electrophysiological technique that objectively reflects the cognitive processing of stimulus from the perspective of detecting and recording neural electrophysiology responses using different paradigms of visual stimuli. Its endogenous components are closely related to advanced psychological activities. This article introduces the characteristics of main endogenous components including visual mismatch negativity (vMMN), N200 and P300, reviews the research progress of visual ERP in the sequelae of brain injury and objective evaluation of visual function, and prospects the application prospect of visual ERP in the field of forensic medicine.

Pre-attentive processing in autism spectrum disorder / 中华行为医学与脑科学杂志

Autism spectrum disorder (ASD) is a neurodevelopmental disorder.Its typical symptoms include social disorder, stereotyped behavior and restrictive interest.In addition, sensory abnormality is also a common symptom of ASD individuals.Pre-attentive processing is an automatic cognitive process that takes place before attention and is independent of consciousness, which reflects the ability to automatically detect changes in the environment of brain.Many researches show that the sensory abnormality and social ability disorder in ASD patients may be related to the defects in the pre-attentive processing stage.Mismatch negativity (MMN) is the most commonly used indicator of pre-attentive processing.ASD individuals show abnormal MMN in response to both social and non-social stimulus.Among them, the pre-attentive processing defect of non-social stimuli in ASD individuals is manifested as the amplitude or latency of MMN induced by single tones, voice or visual stimuli, which is different from that of normal people.The pre-attentive processing defect of social stimuli in ASD individuals is manifested as the amplitude or latency of MMN induced by emotional voice and emotional face, which is different from that of normal people.This result not only helps to find the physiological mechanism of sensory and social disorders in ASD individuals, but also provides theoretical support for MMN as an auxiliary diagnostic index of ASD.Future research on the pre-attentive processing of ASD individuals should pay more attention to enriching the research paradigms of MMN and adopting more kinds of social stimuli.At the same time, the influence of ASD genetic factors on MMN can also be one of the concerns of future research.

The clinical efficacy of treating autistic children using transcranial direct current stimulation / 中华物理医学与康复杂志

Objective:To investigate the effect of transcranial direct current stimulation (tDCS) on the behavior and the mismatch negativity (MMN) component of the auditory evoked potential of autistic children.Methods:Thirty-four autistic children were randomly divided into an anode stimulation group ( n=19) and a pseudo-stimulation group ( n=16). Both groups were given one hour of routine rehabilitation five times a week for 4 weeks, while the anode stimulation group was additionally provided with 20 minutes of tDCS 3 times a week. Before and after the treatment, both groups′ behavior was evaluated by using autism behavior checklist (ABC) as well as any changes in MMN of the auditory evoked EEG signals. Results:There were no significant differences between the two groups in any of the measurements before the treatment. Afterwards behavior had improved significantly in both groups, with significantly greater improvement in the stimulated group. In the stimulated group the average MMN amplitude had increased significantly and the average latency had decreased significantly. However, no such significant changes were observed in the pseudo-stimulation group. There was a significant linear correlation between the changes in the incubation period of MMN components and the improvements in ABC, vestibular functioning, tactile defense and proprioception.Conclusion:Anodal tDCS combined with conventional rehabilitation therapy can effectively increase the MMN amplitude and shorten the latency in autistic children, improving their brain function.

Effects of Electroacupuncture on Consciousness Disorders Based on Transcranial Magnetic Stimulation: Study with Mismatch Negativity / 中国康复理论与实践

Objective:To observe the effect of electroacupuncture based on transcranial magnetic stimulation (TMS) on wakefulness for consciousness disorder. Methods:From January, 2015 to October, 2019, 30 inpatients with consciousness disorder from the General Hospital of Western Theater Command were randomly divided into control group (n = 15) and observetion group (n = 15), Both groups received TMS, and the observetion group received electroacupuncture at Baihui (GV20), Shenting (GV24), bilateral Neiguan (PC6) bilateral Hegu (LI4) and bilateral Yongquan (KI1) in addition, for three months. They were tested the latency of the mismatch negativity (MMN), and assessed with Glasgow Coma Scale (GCS) and persistent vegetative state (PVS) score before, and one month and three months after treatment. Results:The latency of MMN decreased more in the observetion group than in the control group three months after treatment (t = 2.159, P < 0.05). Conclusion:Combination of electroacupuncture on TMS is more effective on wakefulness for consciousness disorder.

Neurophysiological predictors of aphasia recovery in patients with large left-hemispheric infarction: a mismatch negativity study / 中华医学杂志(英文版)

Background@#Although the rehabilitation of aphasia has been extensively studied, the prediction of language outcome still has not received sufficient attention. The aim of this study was to predict the language outcome using mismatch negativity (MMN) in patients with large left-hemispheric infarction.@*Methods@#MMN was elicited by an oddball paradigm in which a standard tone (1000 Hz) and deviant tone (1500 Hz) were presented at 90% and 10% of the number of tones, respectively. The mean amplitudes and laterality indexes (LIs) of MMN were measured over the prefrontal, frontal, central, parietal, temporal, and perisylvian electrodes and both hemispheres during the first 7 days (session 1) and 10 to 20 days (session 2) post-onset. Mixed three-way analysis of variance (ANOVA) was used to investigate differences in these factors between two aphasia groups (the good recovery group and poor recovery group). The predictive value of the most significant LI was also compared with the score of National Institutes of Health Stroke Scale score and low-density volume on computed tomography.@*Results@#A total of 18 patients were enrolled in this study. Mixed three-way ANOVA showed no interaction effect of session × region of interest (ROI) × group (F [3.59, 57.38] = 1.301, P = 0.282) and no interaction effect of ROI × group (F [1.81, 29.01] = 0.71, P= 0.487) and session × group (F [1.00, 16.00]= 0.084, P= 0.776) for MMN amplitude. No interaction effect of session × ROI × group (F [1.79, 28.58] = 0.62, P = 0.530), but an interaction effect of session × group (F [1.00, 16.00] = 5.21, P = 0.036) was found for LIs. In the poor recovery group, the LIs of MMN over all the ROIs, except the parietal area, became more negative at session 2 than those at session 1 (P < 0.05), but this effect was not observed in the good recovery group. Additionally, significant differences were observed in the LIs at session 2 between the two groups (P < 0.05). The LI over the perisylvian area at session 2 had the highest predictive value with an area under the curve of 0.963 (95% confidence interval: 0.884–1.000). An LI score >-0.36 over the perisylvian area suggested good recovery, but a score <-0.36 suggested poor recovery. The LI cut-off value of-0.36 had the highest sensitivity (90.0%) and specificity (87.5%) for predicting a good language outcome at 3 months post-stroke.@*Conclusion@#LIs of MMN amplitudes at approximately 2 weeks post left-hemisphere stroke serve as more sensitive predictors of language outcome, among which the LI over the perisylvian area exhibits the best predictive value.

Event-Related Potentials in Major Depressive Disorder / 신경정신의학

Many event-related potentials (ERPs) studies have been performed in major depressive disorder. ERPs include P50, N170, loudness dependence of auditory evoked potentials (LDAEP), P300, and mismatch negativity (MMN). These ERPs have good time-resolution as noninvasive methods, so they can be used easily in clinical practice and research. For example, ERPs can be used to differentiate patients from healthy people, as well as for assessing the subtype and severity, investigating the psychopathology, and predicting the treatment response in mental disorders. This review focuses on P50, N170, LDAEP, P300, and MMN in major depressive disorders.

Neurophysiological and Psychological Predictors of Social Functioning in Patients with Schizophrenia and Bipolar Disorder

OBJECTIVE: The aim of this study is to examine social functioning in patients with schizophrenia and bipolar disorder and explore the psychological and neurophysiological predictors of social functioning. METHODS: Twenty-seven patients with schizophrenia and thirty patients with bipolar disorder, as well as twenty-five healthy controls, completed measures of social functioning (questionnaire of social functioning), neurocognition (Verbal fluency, Korean-Auditory Verbal Learning Test), and social cognition (basic empathy scale and Social Attribution Task-Multiple Choice), and the childhood trauma questionnaire (CTQ). For neurophysiological measurements, mismatch negativity and heart rate variability (HRV) were recorded from all participants. Multiple hierarchical regression was performed to explore the impact of factors on social functioning. RESULTS: The results showed that CTQ-emotional neglect significantly predicted social functioning in schizophrenia group, while HRV-high frequency significantly predicted social functioning in bipolar disorder patients. Furthermore, emotional neglect and HRV-HF still predicted social functioning in all of the subjects after controlling for the diagnostic criteria. CONCLUSION: Our results implicated that even though each group has different predictors of social functioning, early traumatic events and HRV could be important indicators of functional outcome irrespective of what group they are.

Spatial Properties of Mismatch Negativity in Patients with Disorders of Consciousness / 神经科学通报·英文版

In recent decades, event-related potentials have been used for the clinical electrophysiological assessment of patients with disorders of consciousness (DOCs). In this paper, an oddball paradigm with two types of frequency-deviant stimulus (standard stimuli were pure tones of 1000 Hz; small deviant stimuli were pure tones of 1050 Hz; large deviant stimuli were pure tones of 1200 Hz) was applied to elicit mismatch negativity (MMN) in 30 patients with DOCs diagnosed using the JFK Coma Recovery Scale-Revised (CRS-R). The results showed that the peak amplitudes of MMN elicited by both large and small deviant stimuli were significantly different from baseline. In terms of the spatial properties of MMN, a significant interaction effect between conditions (small and large deviant stimuli) and electrode nodes was centered at the frontocentral area. Furthermore, correlation coefficients were calculated between MMN amplitudes and CRS-R scores for each electrode among all participants to generate topographic maps. Meanwhile, a significant negative correlation between the MMN amplitudes elicited by large deviant stimuli and the CRS-R scores was also found at the frontocentral area. In consequence, our results combine the above spatial properties of MMN in patients with DOCs, and provide a more precise location (frontocentral area) at which to evaluate the correlation between clinical electrophysiological assessment and the level of consciousness.

Uso del Análisis por Componentes Independientes en la extracción de artefactos de la respuesta Mismatch Negativity / Use of Independent Component Analysis in the extraction of Artifacts of the Mismatch Negativity Response

Resumen: El Potencial de disparidad es una respuesta cortical elicitada por la detección automática de estímulos con distintas características, permitiendo la exploración de procesos neuropsicológico. Sin embargo el análisis de esta señal se puede dificultar por una baja relación señal a ruido debida a los artefactos presentes en la adquisición de la misma. Diversas publicaciones proponen el uso de implementaciones de la técnica de Separación Ciega de fuentes, como el Análisis por Componentes Independientes (ACI), para preprocesar las señales y eliminar estos artefactos. Sin em bargo, no se ha estudiado cuál de los algoritmos ACI que se encuentran en la literatura será el óptimo para mejorar la calidad del MMN, por lo que en este estudio se propuso determinar si existen diferencias significativas en las respuestas obtenidas al utilizar los algoritmos de FastICA, Infomax y SOBI para eliminar los artefactos típicamente presentes en este tipo de señales. Adicionalmente se dan algunas características de estos artefactos a manera de sistematizar la identificación y eliminaciones de los mismos, además de comparar las respuestas obtenidas con y sin preprocesamiento, así como la distribución topográfica de este potencial antes y después de la eliminación de artefactos. Mediante el algoritmo Infomax se identifican mejor los Componentes Independientes asociados con artefactos, resultando en un MMN de mayor amplitud y distribución topográfica fronto-central con predominancia izquierda.

Abstract: Mismatch Negativity is a cortical response elicited by the automatic detection of stimuli which have different characteristics, allowing exploration of neuropsychological processes. However, the analysis of this signal can be di fficult by a low SNR due to artifacts present when the signal is recorded. Different publications propose to use the approach given by the Blind Source Separation Technique by means of the Independent Component Analysis (ICA) to preprocess and eliminate these artifacts. Nevertheless, it has not been studied which of the ICA algorithms found in the literature will be optimal for improving the quality of MMN. Therefore the aim of this study is to determine whether there are significant differences in the responses obtained by using FastICA, Infomax and SOBI to remove artifacts typically present in such signals. In addition, some features of the Independent Components related to artifacts are given in order to systematize the identification and elimination of those. In addition, MMN responses obtained with and without data preprocessing, as well as topographic maps before and after the elimination of artifacts were compared. Thus, Infomax is the best ICA algorithm to calculate Independent Components associated with artifacts, resulting in high amplitude MMN and a topographic map with a clear fronto-central distribution with left-hemisphere predominance.

Association of Therapeutic Response and Change of Mismatch Negativity in Schizophrenia Patients

OBJECTIVES: Schizophrenia is characterized by disturbances in perception and cognition. Attenuated mismatch negativity (MMN) reflects central auditory dysfunction in schizophrenia. The aim of this study is to compare MMN changes before and after treatment in schizophrenia patients and to assess their association with treatment response. METHODS: Twenty-three schizophrenia patients underwent an oddball paradigm. MMN was calculated by the difference waveforms of the event-related potentials (ERPs) elicited by subtracting standard from deviant stimulus. The clinical symptoms were measured by the Positive and Negative Syndrome Scale (PANSS), the Psychotic Symptom Rating Scale (PSYRATS). Follow-up evaluation was conducted when the PANSS total score decreased by 30% or more (treatment response group) or before discharge (non-response group). RESULTS: The treatment response group showed significantly larger MMN amplitude improvement and latency reduction than the non-response group after treatment (Fz ; mean amplitude p = 0.035, FCz ; p = 0.041). The auditory hallucination group showed shorter latency than that of the group without hallucinations. Additionally, auditory hallucination was associated with prolonged MMN latency and shortened after treatment in the auditory hallucination response group (Fz ; p = 0.048). CONCLUSIONS: These results suggest that the attenuated MMN amplitude reflects the progression of the disease. The increment of MMN amplitude and shortening of latency after treatment may reflect cognitive functional recovery of central auditory sensory processing.

Effects of sleep epileptiform discharge on aural pre-attentive processing of children with benign childhood epilepsy with central-temporal spikes / 中华实用儿科临床杂志

Objective To explore the relationship between aural pre-attentive processing and non-rapid eye movement(NREM) sleep interictal epileptiform discharge (IED) in children with benign childhood epilepsy with central-temporal spikes (BECTS),in order to provide objective electrophysiological basis for early assessment of cognitive function lesion of BECTS children and intervention.Methods Twenty-nine children diagnosed as BECTS in the Second Affiliated Hospital of Xinxiang Medical University from February 2012 to November 2015 were selected,including 17 males and 12 females,and they were 4-14 years old with average age of (9.17 ±2.42) years,and the course of disease was 0.5-4.0 years.Twenty healthy children who had hospital routine check-up were selected as healthy control group,containing 14 males and 6 females,and they were 5-13 years old with average age of (8.55 ±3.09) years.Mismatch negativity (MMN) test was carried out in both groups,and the MMN amplitudes and latencies were analyzed.The long-term video electroencephalogram (VEEG) monitoring was conducted in the BECTS group to analyze the discharge phases (waking,sleep),locations and the IED indexes.The intergroup MMN indexes and the correlation between MMN and VEEG in the BECTS group were compared.Results The VEEG showed that the sleep structure of BECTS children did not change obviously.All children's epileptiform discharges were located in the Rolandic area,including 11 cases on the left side,8 cases on the right side,and 10 cases on both sides.Epilepsy discharge time:17 patients showed epileptiform discharges in sleep stages only and 12 patients showed epileptiform discharge in both sleep and waking stages.Epileptiform discharges of the 12 patients increased more significantly in sleep stage than thatin waking stage [(40.24 ± 25.15) times/min vs.(1.92 ± 1.38) times/rmin],and the difference was statistically significant (t =5.270,P =0.000).The sample IED index in stage 1 and 2 of NREM was (40.73 ± 10.69) times/min,in which 2 cases had IED indexes ＜ 5 times/min,the IED indexes of 3 cases ＞ 80 times/min who reached electrical status epilepticus during sleep,and others were 17.2-64.6 times/min.Clinical seizures in sleep stages were monitored in only 4 cases,which showed an electro-clinical segregation phenomenon from large quantities of sleep IED.The MMN amplitude was lower in the BECTS group than that in the healthy control group [(6.06 ± 1.89) μV vs.(7.28 ±1.64) μV],and the difference was statistically significant (t =2.346,P =0.025).Latency of BECTS group was longer than that in the healthy control group [(191.37 ±40.13) ms vs.(179.35 ±39.80) ms],but the difference was not statistically significant(t =1.037,P =0.355).Correlation analysis showed that the MMN amplitude was negatively related to discharge phases (r =-0.407,P ＜ 0.05) and the IED indexes (r =-0.644,P ＜ 0.01),and latency was positively related to the IED indexes (r =0.386,P ＜ 0.05),while the other VEEG indexes were not correlated with MMN.Conclusions The BECTS children have aural pre-attentive processing disturbance,especially unconscious automatic processing ability impairment,which weakenattention switch action of automatic processing switching to focused attention processing and fail to filter irrelevant information effectively.Sleep IED is an important factor in impairing the formation and reinforcement of acoustic discrimination and memory trace,interfering the acquisition,processing,storage and matching of new information,which induces children pre-attentive processing disturbance.The MMN may discover the electrophysiological changes of children pre-attentive processing disturbance in early stage.

The Characteristics of Auditory Event-related Potential in Presbycusis Patients / 听力学及言语疾病杂志

Objective To investigate the characteristics of auditory event-related potentials(AERP) mismatch negativity and P300 in presbycusis patients.Methods Auditory event-related potentials were recorded from 20 presbycusis patients, 20 normal hearing elderly subjects and 20 normal young volunteers(the control group) in the Oddball stimulus paradigm.Mismatch negativity(MMN) was tested under the status of reading.P300 was tested under the status of concentrating.The latencies and amplitudes of 3 groups were compared.Results The latency of MMN in the presbycusis patient group(187.38±29.63ms) was significantly longer than those of the normal hearing older group(160.10±23.21±ms)and the control group(148.22±19.30 ms)(P0.05).The latency of P300 in the presbycusis patient group (369.83±27.09 ms) was significantly longer than those of the normal hearing older group(332.89±25.60 ms)and the control group(318.51±22.32ms)(P0.05).Conclusion The presbycusis patients show some central auditory processing dysfunction and cognitive impairment.MMN and P300 might be used as objective methods for evaluating central auditory processing and cognitive function in presbycusis patients.

Predicting Prognosis in Patients with First Episode Psychosis Using Mismatch Negativity : A 1 Year Follow-up Study / 대한정신분열병학회지

OBJECTIVES: It has been shown that early intervention is crucial for favorable outcome in patients with schizophrenia. However, development of biomarkers for predicting prognosis of psychotic disorder still requires more research. In this study, we aimed to investigate whether baseline mismatch negativity (MMN) predict prognosis in patients with first episode psychosis (FEP). METHODS: Twenty-four patients with FEP and matched healthy controls (HCs) were examined with MMN at baseline, and their clinical status were re-assessed after 1 year. Repeated-measures analysis of variance was performed to compare baseline MMN between the two groups. Multiple regression analysis was used to identify factors predicting prognosis in FEP patients during the follow-up period. RESULTS: MMN amplitudes at baseline were significantly reduced in patients with FEP compared to healthy controls. In the multiple regression analysis, baseline MMN amplitude significantly predicted later improvement of performances on digit span and delayed recall of California Verbal Learning Test. However, baseline MMN did not predicted improvement of clinical symptoms. CONCLUSION: These results indicate that MMN may be a possible predictor of improvement in cognitive functioning in patients with FEP. Future study with larger sample and longer follow-up period would be needed to confirm the findings of the current study.

Study on pre-attentive change detection indexed by auditory MMN in undergraduate students with major depressive disorder / 中华行为医学与脑科学杂志

Objective To explore pre-attentive information processing in undergraduate students with major depressive disorder(MDD) indexed by auditory mismatch negativity (MMN) and provide scientific theory basis for the diagnosis of MDD.Methods In the deviant-standard reverse oddball paradigm with deviant stimulus presentation probability of 20％,duration auditory MMN was obtained in 17 MDD university students and 17 gender-/age-matched healthy undergraduate students.All data were analyzed by statistics means of repeated measurement of F test.Results The amplitudes of 150 ms MMN over the frontal-central area were smaller in MDD undergraduate students((-0.34± 1.24) μV) than those in healthy undergraduate students ((-1.07± 1.55) μV,F=24.318,P=0.000).The 50 ms MMN did not differ between MDD students ((-1.96± 1.14) μV) and healthy undergraduate students ((-1.23 ± 1.97) μV,F =0.089,P =0.767).Conclusion Pre-attentive auditory information processing is impaired in MDD undergraduate students.

Measurement of Auditory Discrimination using the Mismatch Negativity (MMN) for the Healthy Youth in the Horizontal Plane / 听力学及言语疾病杂志

Objective To explore whether the changes of sound source in the horizontal azimuth can induce mismatch negativity (MMN) ,and quantify the minimal audible angle which could elicit the MMN and to find effec‐tive way to test human's ability of sound localization in the horizontal plane .Methods With the self developed sound localization device and Bio - logic auditory evoked potentiometer ,in the free field hearing tests were performed on 30 healthy young volunteers according to oddball stimulation sequence .We adopted 1 000 Hz pure tone as the stand‐ard stimuli , the change of sound source location as experimental models ,using minimum audible angle (MAA ) measure procedure ,sound localization test was conducted at 0° ,± 45° ,± 90°standard positions in the horizontal plane .MMN was obtained by subtracting the ERP of deviant stimuli from the ERP of standard stimuli .The latency and amplitude of each MMN were recorded .Results The MMAs of normal young people were recorded and normal values of latency and amplitude of MMN were obtained .The results of the sound localization test for the youth were :MAA(0°)= 2 .09 ± 1 .81° ,MAA( - 45°)= 3 .84 ± 1 .61° ,MAA (45°) = 3 .69 ± 2 .39° ,MAA ( - 90°) = 4 .41 ± 1 . 41° ,MAA(90°)= 4 .23 ± 3 .22° ,separately .There was a significant effect of the location of the deviant stimulus , with those presented at 90° eliciting larger peaks and longer latency period than those presented at 0° .Conclusion Our findings suggest that changes of sound position in the horizontal azimuth can induce mismatch negative waves , and MMN on the basis of MAA test procedure could be used to evaluate the ability of sound localization .

The Effects of Auditory Short-Term Training in Passive Oddball Paradigm with Novel Stimuli

BACKGROUND AND OBJECTIVES: The purpose of this study was to determine how human neural activity might be changed through auditory short-term training when listening to novel stimuli. SUBJECTS AND METHODS: Among the twenty young normal hearing adult listeners who participated, ten were randomly assigned to a training group and ten were assigned to a non-training group as a control. Two synthesized novel stimuli were used: /su/ and /integralu/. Both stimuli similarly sounded like /su/, but had two different onset transition frequencies and fricative pole frequencies. In the experiment, behavioral identification test (i.e., /su/ vs. /integralu/) and the mismatch negativity (MMN) were measured before and after training for the training group. To gauge the training effect, the listeners in the training group were taught by discrimination and identification of two novel stimuli for about 20 minutes. RESULTS: The results showed that scores for the behavioral test increased significantly after auditory short-term training. Also, onset latency, duration, and area of the MMN were significantly changed when elicited by the training stimuli. CONCLUSIONS: These findings indicated that auditory short-term training could change human neural activity, suggesting future clinical applications for auditory training.

Association between Mismatch Negativity and Functional Status in Patients with Schizophrenia / 대한정신분열병학회지

OBJECTIVES: It has been constantly reported that mismatch negativity (MMN) is impaired in patients with schizophrenia. However, the mechanism which relates impaired MMN and schizophrenia is not clear yet. The aim of this study is to investigate the association between MMN and clinical variables including functional status in patients with schizophrenia. METHODS: The present study assessed MMN using passive auditory oddball task in 26 patients with schizophrenia and 48 healthy controls. Repeated measures Analysis of Variance with age as a covariate was carried out for comparing peak amplitude and latency of MMN at 8 central line electrodes (FPz, Fz, FCz, Cz, CPz, Pz, POz, Oz) across groups. Pearson's correlation was performed to reveal the relationship between MMN and clinical variables including neurocognitive test results and the Global Assessment of Functioning score. RESULTS: MMN amplitude was significantly reduced in patients with schizophrenia compared with healthy controls. Pearson's correlation showed that subsets of short form of Korean Wechsler Adult Intelligence Scale scores and GAF scores were associated with MMN amplitude in patients with schizophrenia. CONCLUSION: These findings suggest that MMN amplitude is associated with current functional status including cognitive function in patients with schizophrenia.