Mismatch Negativity Latency Research Articles

Further characterization of "subject's own name (SON) negativity," an ERP component reflecting early preattentive detection of SON.

BackgroundSubject’s own name (SON) is detected automatically and unconsciously in the brain. SON negativity, an early wave in the mismatch negativity latency range, has been proposed as a potential event-related potential (ERP) index of the automatic preattentive detection of SON. SON negativity is probably not a general measure of familiarity, as it is not elicited by the subject’s parent’s name. We further investigated the specificity of this response by testing whether it is elicited by a name to which subjects were strongly but only temporarily familiarized.FindingsSubjects performed a task to detect an arbitrary unfamiliar name for forty minutes. Then, that name was presented randomly and equiprobably with nine novel unfamiliar names while they played a video game and tried to ignore the sounds. SON negativity was not elicited, even when subjects spontaneously noticed hearing the familiarized name.ConclusionsThe finding supports the notion that SON negativity represents a specific ERP measure of the early preattentive detection of SON, rather than a general measure of familiarity.

Mismatch Negativity Latency as a Biomarker of Amnestic Mild Cognitive Impairment in Chinese Rural Elders

The aim was to evaluate the mismatch negativity (MMN) component, a correlate of the automatic detection of changes in the acoustic environment, in healthy adults, and adults with amnestic mild cognitive impairment (aMCI). Forty-three aMCI subjects and 43 healthy Chinese older adults were arranged into experimental group and control group, respectively. Their MMN amplitude and latency were measured at the FZ, FCZ, and CZ electrode sites under a passive auditory oddball task. The results showed that the latencies obtained from the FZ, FCZ, and CZ electrode sites were significantly longer in the aMCI adults than in the control adults (P < 0.01) while there were no significant differences in MMN amplitude between two groups (P > 0.05). The MMN latency was found to be a sensitive and specific biomarker of aMCI.

Early Auditory Deviance Detection and Functional Outcome in Patients with Schizophrenia

Introduction The Mismatch Negativity (MMN) is an event-related potential (ERP) sensitive to early auditory deviance detection and has been shown to be reduced in patients with schizophrenia. Moreover, MMN amplitude reduction to duration deviant tones was found to be related to functional outcomes particularly, to social cognition and real-life functioning. Objectives In the context of a multicentre study of the Italian Network for Research on Psychoses, our study focused on the investigation of early auditory discrimination components in relation to functioning in real-life in patients with schizophrenia. Methods ERPs were recorded in 64 chronic, stabilized patients with schizophrenia during the presentation of standard, duration deviants and frequency deviants tones while watching a cartoon. The Specific Level of Functioning (SLOF) scale was used to measure real-life functioning. Psychopathology, neurocognition and social cognition were measured by state of art instruments. Regression analyses were carried out using SLOF domains as dependent variables and MMN, psychopathology, neurocognition, extrapyramidal symptoms and social cognition as independent predictors. Results Latency of MMN entered the regression equation only for the SLOF domain of common activities explaining less variance than social cognition and positive symptoms. Conclusion In stabilized patients with schizophrenia pre-attentive deficits, as indexed by MMN and P3a amplitude reduction, do not show any association with psychopathology or functioning. Latency of MMN was an independent predictor of some aspects of functioning with a smaller effect than social cognition and psychopathology domains.

Neural correlates of individual differences in processing of rising tones in Cantonese: Implications for speech perception and production

Neural correlates of individual differences in processing of rising tones in Cantonese: Implications for speech perception and production

Testosterone modulates preattentive sensory processing and involuntary attention switches to emotional voices

Testosterone is capable of altering facial threat processing. Voices, similar to faces, convey social information. We hypothesized that administering a single dose of testosterone would change voice perception in humans. In a placebo-controlled, randomly assigned, double-blind crossover design, we administered a single dose of testosterone or placebo to 18 healthy female volunteers and used a passive auditory oddball paradigm. The mismatch negativity (MMN) and P3a in responses to fearfully, happily, and neutrally spoken syllables dada and acoustically matched nonvocal sounds were analyzed, indicating preattentive sensory processing and involuntary attention switches. Results showed that testosterone administration had a trend to shorten the peak latencies of happy MMN and significantly enhanced the amplitudes of happy and fearful P3a, whereas the happy- and fearful-derived nonvocal MMN and P3a remained unaffected. These findings demonstrated acute effect of testosterone on the neural dynamics of voice perception. Administering a single dose of testosterone modulates preattentive sensory processing and involuntary attention switches in response to emotional voices.

Mental ability and information processing during discrimination of auditory motion patterns: Effects on P3 and mismatch negativity

The relation between mental ability (MA), indexed by scores on Raven Advanced Progressive Matrices (RAPM), and the ability to detect auditory motion patterns was examined using P300 and mismatch negativity (MMN) measures of the ERPs. Forty-nine female volunteers were presented with two blocks of binaural sound stimuli each containing identical standards (90%), creating an immobile sound image located along the midline of the head, and deviants (10%) modeling movement of the midline sound image towards the left ear. Sound stimuli were presented in passive (ignore) and then active response conditions. Task difficulty was manipulated by introducing two moving sound sequences into the deviant stimuli, one in which the inter-aural delay (IAD) varied linearly from 0 to 0.8 ms (long-IAD), and the other in which IAD varied from 0 to 0.4 ms (short-IAD). In the active moving sound discrimination condition, the greater difficulty for the short-IAD was confirmed by reduced accuracy, longer response times, and greater variability in response times than those for long-IAD. Predominantly in the active more difficult condition, higher ability (HA) was associated with greater response accuracy, shorter response times, and shorter P300 latency, while the association with P300 amplitude was not significant. These effects are indicative of the greater speed in stimulus processing and greater facility in discrimination of simulated auditory motion patterns for HA than for lower ability (LA) individuals. In the passive condition HA was associated with shorter MMN latency and larger MMN amplitude to the deviant sounds in the long-IAD condition (higher deviance magnitude). These effects not only demonstrate the importance of both mental speed and discrimination ability for MA, but also indicate that higher order discrimination, as that requiredforsimulatedauditory motion,develops prior toconsciousness, andcannot be attributed to conscious processes like focused attention.

Reduced neural integration of letters and speech sounds in dyslexic children scales with individual differences in reading fluency.

The acquisition of letter-speech sound associations is one of the basic requirements for fluent reading acquisition and its failure may contribute to reading difficulties in developmental dyslexia. Here we investigated event-related potential (ERP) measures of letter-speech sound integration in 9-year-old typical and dyslexic readers and specifically test their relation to individual differences in reading fluency. We employed an audiovisual oddball paradigm in typical readers (n = 20), dysfluent (n = 18) and severely dysfluent (n = 18) dyslexic children. In one auditory and two audiovisual conditions the Dutch spoken vowels/a/and/o/were presented as standard and deviant stimuli. In audiovisual blocks, the letter ‘a’ was presented either simultaneously (AV0), or 200 ms before (AV200) vowel sound onset. Across the three children groups, vowel deviancy in auditory blocks elicited comparable mismatch negativity (MMN) and late negativity (LN) responses. In typical readers, both audiovisual conditions (AV0 and AV200) led to enhanced MMN and LN amplitudes. In both dyslexic groups, the audiovisual LN effects were mildly reduced. Most interestingly, individual differences in reading fluency were correlated with MMN latency in the AV0 condition. A further analysis revealed that this effect was driven by a short-lived MMN effect encompassing only the N1 window in severely dysfluent dyslexics versus a longer MMN effect encompassing both the N1 and P2 windows in the other two groups. Our results confirm and extend previous findings in dyslexic children by demonstrating a deficient pattern of letter-speech sound integration depending on the level of reading dysfluency. These findings underscore the importance of considering individual differences across the entire spectrum of reading skills in addition to group differences between typical and dyslexic readers.

Mental ability and information processing during discrimination of auditory motion patterns: Effects on P300 and mismatch negativity

The relation between mental ability (MA), indexed by scores on Raven Advanced Progressive Matrices (RAPM), and the ability to detect auditory motion patterns was examined using P300 and mismatch negativity (MMN) measures of the ERPs. Forty-nine female volunteers were presented with two blocks of binaural sound stimuli each containing identical standards (90%), creating an immobile sound image located along the midline of the head, and deviants (10%) modeling movement of the midline sound image towards the left ear. Sound stimuli were presented in passive (ignore) and then active response conditions. Task difficulty was manipulated by introducing two moving sound sequences into the deviant stimuli, one in which the inter-aural delay (IAD) varied linearly from 0 to 0.8ms (long-IAD), and the other in which IAD varied from 0 to 0.4ms (short-IAD). In the active moving sound discrimination condition, the greater difficulty for the short-IAD was confirmed by reduced accuracy, longer response times, and greater variability in response times than those for long-IAD. Predominantly in the active more difficult condition, higher ability (HA) was associated with greater response accuracy, shorter response times, and shorter P300 latency, while the association with P300 amplitude was not significant. These effects are indicative of the greater speed in stimulus processing and greater facility in discrimination of simulated auditory motion patterns for HA than for lower ability (LA) individuals. In the passive condition HA was associated with shorter MMN latency and larger MMN amplitude to the deviant sounds in the long-IAD condition (higher deviance magnitude). These effects not only demonstrate the importance of both mental speed and discrimination ability for MA, but also indicate that higher order discrimination, as that required for simulated auditory motion, develops prior to consciousness, and cannot be attributed to conscious processes like focused attention.

Auditory stream segregation using bandpass noises: evidence from event-related potentials.

The current study measured neural responses to investigate auditory stream segregation of noise stimuli with or without clear spectral contrast. Sequences of alternating A and B noise bursts were presented to elicit stream segregation in normal-hearing listeners. The successive B bursts in each sequence maintained an equal amount of temporal separation with manipulations introduced on the last stimulus. The last B burst was either delayed for 50% of the sequences or not delayed for the other 50%. The A bursts were jittered in between every two adjacent B bursts. To study the effects of spectral separation on streaming, the A and B bursts were further manipulated by using either bandpass-filtered noises widely spaced in center frequency or broadband noises. Event-related potentials (ERPs) to the last B bursts were analyzed to compare the neural responses to the delay vs. no-delay trials in both passive and attentive listening conditions. In the passive listening condition, a trend for a possible late mismatch negativity (MMN) or late discriminative negativity (LDN) response was observed only when the A and B bursts were spectrally separate, suggesting that spectral separation in the A and B burst sequences could be conducive to stream segregation at the pre-attentive level. In the attentive condition, a P300 response was consistently elicited regardless of whether there was spectral separation between the A and B bursts, indicating the facilitative role of voluntary attention in stream segregation. The results suggest that reliable ERP measures can be used as indirect indicators for auditory stream segregation in conditions of weak spectral contrast. These findings have important implications for cochlear implant (CI) studies—as spectral information available through a CI device or simulation is substantially degraded, it may require more attention to achieve stream segregation.

Mismatch negativity in recent-onset and chronic schizophrenia: a current source density analysis.

Mismatch negativity (MMN) is a component of the event-related potential elicited by deviant auditory stimuli. It is presumed to index pre-attentive monitoring of changes in the auditory environment. MMN amplitude is smaller in groups of individuals with schizophrenia compared to healthy controls. We compared duration-deviant MMN in 16 recent-onset and 19 chronic schizophrenia patients versus age- and sex-matched controls. Reduced frontal MMN was found in both patient groups, involved reduced hemispheric asymmetry, and was correlated with Global Assessment of Functioning (GAF) and negative symptom ratings. A cortically-constrained LORETA analysis, incorporating anatomical data from each individual's MRI, was performed to generate a current source density model of the MMN response over time. This model suggested MMN generation within a temporal, parietal and frontal network, which was right hemisphere dominant only in controls. An exploratory analysis revealed reduced CSD in patients in superior and middle temporal cortex, inferior and superior parietal cortex, precuneus, anterior cingulate, and superior and middle frontal cortex. A region of interest (ROI) analysis was performed. For the early phase of the MMN, patients had reduced bilateral temporal and parietal response and no lateralisation in frontal ROIs. For late MMN, patients had reduced bilateral parietal response and no lateralisation in temporal ROIs. In patients, correlations revealed a link between GAF and the MMN response in parietal cortex. In controls, the frontal response onset was 17 ms later than the temporal and parietal response. In patients, onset latency of the MMN response was delayed in secondary, but not primary, auditory cortex. However amplitude reductions were observed in both primary and secondary auditory cortex. These latency delays may indicate relatively intact information processing upstream of the primary auditory cortex, but impaired primary auditory cortex or cortico-cortical or thalamo-cortical communication with higher auditory cortices as a core deficit in schizophrenia.

Effects of Recurrent Acute Otitis Media on Cortical Speech-Sound Processing in 2-Year Old Children

To investigate at the age of 2 years the effects of childhood recurrent acute otitis media (RAOM) on central auditory processing by using cortical event-related potentials elicited by syllable stimuli. During a 1-year period, 22- to 26-month-old children fulfilling the criteria for tympanostomy tube insertion in Oulu University Hospital, Oulu, Finland, were recruited to the RAOM group (N = 20). The control group (N = 19) was matched by age, sex, and mother's educational level. In both groups, children were typically developing and had no family history of language disorder or developmental language problems. Finnish syllables /ke:/ and /pi:/ as standards and their variants with changes in frequency, intensity, vowel, consonant, and vowel duration as deviants were used to record P1, N2, and mismatch negativity (MMN) responses in the multifeature paradigm. The clinically healthy ears at the time of registration were a prerequisite for the participation. Children with RAOM and their controls showed the age-typical P1 and N2 responses with no differences in the amplitudes or latencies between the groups, which suggests unaffected basic encoding of sound features and sound representation formation. However, the groups showed different auditory discrimination profiles. In children with RAOM, frequency and vowel MMN amplitudes were increased. Furthermore, the MMN latency for the frequency change was shorter and the frequency MMN amplitude lateralized to the left hemisphere in the RAOM group instead of an adult-like right-hemispheric lateralization observed in the controls. The children with RAOM had a more anterior MMN amplitude scalp distribution for the intensity change than control children. In addition, the MMN amplitude elicited by consonant change was evenly distributed unlike in controls, who had a left-side preponderant lateralization. Taken together, these results suggest an elevated responsiveness for frequency, vowel, and intensity changes, and an immature pattern of discriminating small speech sound contrasts in children with RAOM. The results suggest that childhood RAOM does not affect the central auditory pathway integrity or sound encoding. However, RAOM may lead to aberrant preattentive discrimination of sound features even when the peripheral auditory input is normal. These results are clinically significant because even transient problems with auditory processing may delay language development.

Mismatch negativity latency and cognitive function in schizophrenia.

BackgroundThe Mismatch Negativity (MMN) is an event-related potential (ERP) sensitive to early auditory deviance detection and has been shown to be reduced in schizophrenia patients. Moreover, MMN amplitude reduction to duration deviant tones was found to be related to functional outcomes particularly, to neuropsychological (working memory and verbal domains) and psychosocial measures. While MMN amplitude is thought to be correlated with deficits of early sensory processing, the functional significance of MMN latency remains unclear so far. The present study focused on the investigation of MMN in relation to neuropsychological function in schizophrenia.MethodForty schizophrenia patients and 16 healthy controls underwent a passive oddball paradigm (2400 binaural tones; 88% standards [1 kHz, 80 db, 80 ms], 11% frequency deviants [1.2 kHz], 11% duration deviants [40 ms]) and a neuropsychological test-battery. Patients were assessed with regard to clinical symptoms.ResultsCompared to healthy controls schizophrenia patients showed diminished MMN amplitude and shorter MMN latency to both deviants as well as an impaired neuropsychological test performance. Severity of positive symptoms was related to decreased MMN amplitude to duration deviants. Furthermore, enhanced verbal memory performance was associated with prolonged MMN latency to frequency deviants in patients.ConclusionThe present study corroborates previous results of a diminished MMN amplitude and its association with positive symptoms in schizophrenia patients. Both, the findings of a shorter latency to duration and frequency deviants and the relationship of the latter with verbal memory in patients, emphasize the relevance of the temporal aspect of early auditory discrimination processing in schizophrenia.

Intelligence and information processing during discrimination of auditory motion patterns: Effects on P3 and mismatch negativity

The relation between mental ability and auditory motion discrimination ability was examined by recording mismatch negativity (MMN) and event-related potentials responses during two conditions differing in task difficulty. Participants were exposed to two blocks of sound stimuli each containing identical standards (90%) creating an immobile sound image located along the midline of the head, and one of a set of deviants (10%) creating a sound image moving from the midline of the head towards the left ear. Higher ability (HA) group exhibited greater response accuracy, shorter response times, smaller P3 amplitude, and shorter P3 latency to target stimuli than the lower ability (LA) group. When subjects were instructed to ignore the stimuli, higher ability (HA) was associated with larger MMN amplitude and shorter MMN latency at centroparietal and frontotemporal leads to infrequent deviant stimuli. MMN findings indicate that HA individuals have better auditory discrimination of signals with different localizing characteristics.

Attention effects on auditory scene analysis: insights from event-related brain potentials

Sounds emitted by different sources arrive at our ears as a mixture that must be disentangled before meaningful information can be retrieved. It is still a matter of debate whether this decomposition happens automatically or requires the listener's attention. These opposite positions partly stem from different methodological approaches to the problem. We propose an integrative approach that combines the logic of previous measurements targeting either auditory stream segregation (interpreting a mixture as coming from two separate sources) or integration (interpreting a mixture as originating from only one source). By means of combined behavioral and event-related potential (ERP) measures, our paradigm has the potential to measure stream segregation and integration at the same time, providing the opportunity to obtain positive evidence of either one. This reduces the reliance on zero findings (i.e., the occurrence of stream integration in a given condition can be demonstrated directly, rather than indirectly based on the absence of empirical evidence for stream segregation, and vice versa). With this two-way approach, we systematically manipulate attention devoted to the auditory stimuli (by varying their task relevance) and to their underlying structure (by delivering perceptual tasks that require segregated or integrated percepts). ERP results based on the mismatch negativity (MMN) show no evidence for a modulation of stream integration by attention, while stream segregation results were less clear due to overlapping attention-related components in the MMN latency range. We suggest future studies combining the proposed two-way approach with some improvements in the ERP measurement of sequential stream segregation.

Evaluation of Auditory Cortical Development in the Early Stages of Post Cochlear Implantation Using Mismatch Negativity Measurement

The aim of this study was to investigate auditory cortical development using mismatch negativity (MMN) in prelingual severe-to-profound hearing-impaired children from the stage of cochlear implant (CI) power-up to 6 months after power-up. Eighteen children were recruited and examined at the stage of CI initial power-up (M0), as well as several follow-up periods, that is, 1 month (M1), 3 months (M3), and 6 months (M6) after CI power-up. The MMN responses were measured using a 128-Channel Dense Array EEG System. The group average and individual MMN analysis were used to investigate the longitudinal changes of the MMN characteristics. The relationship between MMN characteristics and scores of categories of auditory performance (CAP) was also investigated. Although the MMN incidence was much lower at the periods of M0 and M1, significantly higher MMN incidence was found in M3 and M6. The MMN latencies decreased significantly from M3 to M6, but no significant difference in the amplitudes was found between these periods. There was a negative correlation between the increment of CAP scores and decrement of MMN latency from M3 to M6. MMN incidence increment and latency decrement are likely to be the objective and noninvasive indicators for evaluating auditory central development at an early stage in children after cochlear implantation. Moreover, the latency decrement from M3 to M6 correlated significantly with the increment of the CAP scores, indicating a fast maturation period, which might be a key period for auditory rehabilitation.

Anterior Cingulate Abnormality as a Neural Correlate of Mismatch Negativity in Schizophrenia

Background: Limbic circuitry, especially the anterior cingulate gyrus, has been implicated in the pathophysiology and cognitive changes of schizophrenia. Previous diffusion tensor imaging studies have demonstrated that the integrity of the anterior cingulum (AC) is abnormal in schizophrenia. However, the relationship between the abnormal AC tract integrity and the pathophysiology of schizophrenia has not been fully studied. Methods: We performed a voxelwise group comparison of white matter fractional anisotropy (FA) by using tract-based spatial statistics in 9 patients with schizophrenia and 9 matched controls. We then measured FA specifically in the AC by using a tract-specific measurement. The latency and amplitude of the mismatch negativity (MMN) were also evaluated in all subjects. Results: In patients with schizophrenia, tract-based spatial statistics showed a reduction in FA in broad white matter areas, including the bilateral AC, compared with controls. Tract-specific measurements confirmed the specific reduction of FA in the region of the bilateral AC. The decreased FA in the AC was correlated with prolonged MMN latency in the patient group. Conclusion: Our study of AC structure and electrophysiological changes in schizophrenia suggest that the disruption of limbic-cortical structural networks may be part of the neural basis underlying the changes in MMN in schizophrenia.

Preattentive processing of horizontal motion, radial motion, and intensity changes of sounds

Localization of sound sources is critical for an appropriate behavioral response. This is not only true for localization in the horizontal plane but also for localization in depth. Depth ranging of sound sources implicates various distance cues, among others sound intensity. In this study, we measured human electroencephalography and compared mismatch negativity (MMN) amplitudes and latencies for horizontal motion, radial motion, and pure intensity changes in the free field. We observed similar MMN latencies for horizontal and radial motion, whereas MMN responses to pure intensity changes were comparably delayed. MMN amplitudes and latencies were not different for approaching and receding sounds. Our data suggest similar fast processing for horizontal and radial motion, whereas pure intensity changes are possibly processed with less priority.

S12-1. MMN in psychological research – A study of change in MMN peak latencies

In order to investigate how sound representations are compressed in sensory memory, we examined mismatch negativity (MMN), ERP component reflecting neural representations in sensory memory. Yabe et al. (2005) showed that the MMNm peak latencies by reversing standards to deviants from oddball sequences did not reflect physical time flow, and they suggested that the temporal information could be compressed in sensory memory. However, it is not clear that factors of the asymmetrical change in MMN peak latencies. The experiment 1 compared the conditions of the stimuli that included a silence gap and it replaced by a tone segment which was decreased intensity. As a result, duplicates as the finding of Yabe et al., and it indicates that the whole stimulus duration rather than only gap duration is compressed in sensory memory. The experiment 2 showed that the stimuli’s saliency affects the peak latency of MMN, examined by changing in sound intensity. The experiment 3 that examined to effect of stimuli’s duration, suggested that stimuli’s temporal element and saliency affect the asymmetrical change in MMN peak latencies. These findings suggest the temporal element of whole auditory stimulus are compress in neural representations and it is influenced by a saliency of stimulus.

Reduced P3a amplitudes in antipsychotic naïve first-episode psychosis patients and individuals at clinical high-risk for psychosis

Event related potentials (ERP) associated with early sensory information processing have been proposed as possible vulnerability markers for psychosis. Compared to other ERPs reported in schizophrenia research, like Mismatch Negativity (MMN), little is known about P3a, an ERP related to novelty detection. The aim of this study was to analyze the MMN-P3a complex in 20 antipsychotic naïve first-episode psychosis patients (FEP), 23 antipsychotic naïve individuals at clinical high-risk for psychosis (CHR) and 24 healthy controls. The MMN-P3a amplitudes and latencies were obtained during a passive auditory mismatch frequency deviant ERP paradigm and analyzed in frontal and central scalp regions. There were no significant differences in MMN amplitude between groups. There was a significant group difference in P3a due to reduced amplitude (F[2,64] = 3.7, p = 0.03) in both CHR and FEP groups (Mean difference (MD) = 0.39, p = 0.04 and MD = 0.49, p = 0.02, respectively) compared to the control group and this effect was most prominent on the right side (Group × laterality effect: MD = 0.57, p < 0.01 and MD = 0.58, p < 0.01, respectively). No significant differences were observed for MMN or P3a latencies between groups. Although a P3a decrement in chronic schizophrenia and FEP has been previously reported, our results suggest that this novelty detection impairment is present even in pre-psychosis stages in antipsychotic naïve subjects. This study supports the evidence that P3a could represent a neurophysiological vulnerability marker for the development of psychosis.

Reduced duration mismatch negativity in adolescents with psychotic symptoms: further evidence for mismatch negativity as a possible biomarker for vulnerability to psychosis

BackgroundDeficits in the mismatch negativity (MMN) and P3a components are the most reliable and robust findings in schizophrenia. These abnormalities have also been recently documented in individuals clinically at risk for psychosis, indicating that the MMN may be a potential biomarker for psychosis. However, the at risk samples included in MMN studies are characterised by pre-existing clinical symptomatology and significant functional decline which are related to MMN amplitude. These factors may be potential confounds in determining whether deficient MMN is present prior to clinical manifestation of the disorder. Therefore, investigating the MMN in the extended psychosis phenotype comprising adolescents with psychotic symptoms from the general population may provide important information on whether abnormal MMN is apparent in the earliest stages of risk.MethodsThirty six adolescents completed a duration deviant MMN task. Fourteen adolescents with psychotic symptoms comprised the at risk group and 22 with no psychotic symptoms comprised the Controls. The task consisted of 85% standard tones (25 ms) and 15% deviant tones (50 ms). The groups were compared on MMN and P3a amplitude and latency across frontocentral and temporal electrodes.ResultsAdolescents with psychotic symptoms were characterised by a reduction in MMN amplitude at frontal and temporal regions compared to the controls.ConclusionsThis is the first study to demonstrate impaired auditory discrimination for duration deviant tones in nonclinical adolescents with psychotic symptoms. These findings suggest that MMN amplitude may be a possible biomarker for vulnerability to psychosis.