MMN Responses Research Articles

Predictions about prosody facilitate lexical access: Evidence from P50/N100 and MMN components

Research into the neural foundation of perception asserts a model where top-down predictions modulate the bottom-up processing of sensory input. Despite becoming increasingly influential in cognitive neuroscience, the precise account of this predictive coding framework remains debated. In this study, we aim to contribute to this debate by investigating how predictions about prosody facilitate speech perception, and to shed light especially on lexical access influenced by simultaneous predictions in different domains, inter alia, prosodic and semantic. Using a passive auditory oddball paradigm, we examined neural responses to prosodic changes, leading to a semantic change as in Dutch nouns canon [ˈkaːnɔn] ‘canon’ vs kanon [kaːˈnɔn] ‘cannon’, and used acoustically identical pseudowords as controls. Results from twenty-eight native speakers of Dutch (age range 18–32 years) indicated an enhanced P50/N100 complex to prosodic change in pseudowords as well as an MMN response to both words and pseudowords. The enhanced P50/N100 response to pseudowords is claimed to indicate that all relevant auditory information is still processed by the brain, whereas the reduced response to words might reflect the suppression of information that has already been encoded. The MMN response to pseudowords and words, on the other hand, is best justified by the unification of previously established prosodic representations with sensory and semantic input respectively. This pattern of results is in line with the predictive coding framework acting on multiple levels and is of crucial importance to indicate that predictions about linguistic prosodic information are utilized by the brain as early as 50 ms.

Nuances in intensity deviant asymmetric responses as a biomarker for tinnitus.

We attempted to replicate a potential tinnitus biomarker in humans based on the Sensory Precision Integrative Model of Tinnitus called the Intensity Mismatch Asymmetry. A few advances on the design were also included, including tighter matching of participants for gender, and a control stimulus frequency of 1 kHz to investigate whether any differences between control and tinnitus groups are specific to the tinnitus frequency or domain-general. The expectation was that there would be asymmetry in the MMN responses between tinnitus and control groups at the tinnitus frequency, but not at the control frequency, where the tinnitus group would have larger, more negative responses to upward deviants than downward deviants, and the control group would have the opposite pattern or lack of a deviant direction effect. However, no significant group differences were found. There was a striking difference in response amplitude to control frequency stimuli compared to tinnitus frequency stimuli, which could be an intrinsic quality of responses to these frequencies or could reflect high frequency hearing loss in the sample. Additionally, the upward deviants elicited stronger MMN responses in both groups at tinnitus frequency, but not at the control frequency. Factors contributing to these discrepant results at the tinnitus frequency could include hyperacusis, attention, and wider contextual effects of other frequencies used in the experiment (i.e. the control frequency in other blocks).

Consonance Perception in Congenital Amusia: Behavioral and Brain Responses to Harmonicity and Beating Cues.

Congenital amusia is a neurodevelopmental disorder characterized by difficulties in the perception and production of music, including the perception of consonance and dissonance, or the judgment of certain combinations of pitches as more pleasant than others. Two perceptual cues for dissonance are inharmonicity (the lack of a common fundamental frequency between components) and beating (amplitude fluctuations produced by close, interacting frequency components). Amusic individuals have previously been reported to be insensitive to inharmonicity, but to exhibit normal sensitivity to beats. In the present study, we measured adaptive discrimination thresholds in amusic participants and found elevated thresholds for both cues. We recorded EEG and measured the MMN in evoked potentials to consonance and dissonance deviants in an oddball paradigm. The amplitude of the MMN response was similar overall for amusic and control participants; however, in controls, there was a tendency toward larger MMNs for inharmonicity than for beating cues, whereas the opposite tendency was observed for the amusic participants. These findings suggest that initial encoding of consonance cues may be intact in amusia despite impaired behavioral performance, but that the relative weight of nonspectral (beating) cues may be increased for amusic individuals.

Probing early lexical and morphological processing in Dutch with the MMN response

The past tense inflection has been a popular phenomenon to study the representational status of morphologically complex words. While several experiments in the processing of past tense verbs across languages have shown these verbs are stored via their constituent morphemes, experiments in the processing of the Dutch past tense indicate that these words are lexically stored in their surface form and therefore not decomposed. However, the experiments in Dutch past tense processing have not made use of experimental paradigms that can tap the earliest stages of word processing, where some theories predict decomposition would take place. We used the mismatch negativity response to study the representational status of monomorphemic and morphologically complex Dutch words. We were able to obtain different responses for monomorphemic and morphologically complex words, suggesting these are processed by different mechanisms. We cannot, however, discard the possibility that some past tense forms in Dutch do have surface form representations.

Electrically evoked mismatch negativity responses to loudness and pitch cues in cochlear implant users

Objective measurements could improve cochlear implant (CI) fitting, especially for CI users who have difficulty assessing their hearing impressions. In this study, we investigated the electrically evoked mismatch negativity (eMMN) brain potential as a mainly preattentive response to pitch and loudness changes. In an electrophysiological exploratory study with 21 CI users, pitch and loudness cues were presented in controlled oddball paradigms that directly electrically stimulated the CI via software. Out of them 17 valid data sets were analyzed. A pitch cue was produced by changing the stimulating CI electrodes (pairs of adjacent electrodes). A loudness cue originated from changing the stimulation amplitude on one CI electrode. MMN responses were measured unsing clinical electroencephalography recording according to a standard recording protocol. At the group level, significant eMMN responses were elicited for loudness cues and for pitch cues at basal electrode pairs but not at apical electrode pairs. The effect of deviance direction was not significant and no stimulus artifacts were observed. Recording an electrically evoked MMN in response to loudness changes in CI users is generally feasible, and is, therefore, promising to support CI fitting procedures in the future. Detection of pitch cues would require a greater electrode distance between selected electrodes for standard and deviant stimuli, especially in apical regions. A routine clinical setup can be used to measure eMMN.

Evidence for predictions established by phantom sound

Predictions, the bridge between the internal and external worlds, are established by prior experience and updated by sensory stimuli. Responses to omitted but unexpected stimuli, known as omission responses, can break the one-to-one mapping of stimulus-response and can expose predictions established by the preceding stimulus built up. While research into exogenous predictions (driven by external stimuli) is often reported, that into endogenous predictions (driven by internal percepts) is rarely available in the literature. Here, we report evidence for endogenous predictions established by the Zwicker tone illusion, a phantom pure-tone-like auditory percept following notch noises. We found that MMN, P300, and theta oscillations could be recorded using an omission paradigm in subjects who can perceive Zwicker tone illusions, but could not in those who cannot. The MMN and P300 responses relied on attention, but theta oscillations did not. In-depth analysis shows that an increase in single-trial theta power, including total and induced theta, with the endogenous prediction, is lateralized to the left frontal brain areas. Our study depicts that the brain automatically analyzes internal perception, progressively establishes predictions and yields prediction errors in the left frontal region when a violation occurs.

A Preliminary Study Characterizing Subcortical and Cortical Auditory Processing and Their Relation to Autistic Traits and Sensory Features.

This study characterizes the subcortical auditory brainstem response (speech-ABR) and cortical auditory processing (P1 and Mismatch Negativity; MMN) to speech sounds and their relationship to autistic traits and sensory features within the same group of autistic children (n = 10) matched on age and non-verbal IQ to their typically developing (TD) peers (n = 21). No speech-ABR differences were noted, but autistic individuals had larger P1 and faster MMN responses. Correlations revealed that larger P1 amplitudes and MMN responses were associated with greater autistic traits and more sensory features. These findings highlight the complexity of the auditory system and its relationships to behaviours in autism, while also emphasizing the importance of measurement and developmental matching.

Mismatch negativity and P3a amplitude in children with familial high risk of schizophrenia or bipolar disorder – A Danish register-based EEG study

BackgroundInfrequent deviants in a rapid sequence of sounds elicit a negative cortical potential over the frontocentral midline (mismatch negativity, MMN) followed by a positive deflection (P3a). Both cortical potentials are consistently attenuated in patients with schizophrenia (SZ), and, to a lesser degree, in patients with bipolar disorder (BP). ObjectiveSince it is unclear when MMN and P3a deficits arise relative to the emergence of symptoms, we examined whether MMN and P3a alterations are already detectable in children with familial high risk. MethodsUsing 128-channel electroencephalography, we recorded auditory MMN and P3a evoked by a deviation in sound duration, frequency, or both in 51 children with familial high-risk for SZ (FHR-SZ), 41 children with familial high-risk for BP (FHR-BP), and 39 population-based children (PBC) at a mean age of 12.10. ResultsMMN amplitude evoked by a duration deviant was larger in children with FHR-BP compared to PBC and FHR-SZ. P3a amplitude in response to a duration ∗ frequency deviant was larger in children with FHR-BP compared to children with FHR-SZ, but not compared to PBC. MMN- and P3a-peak latency did not differ between groups. ConclusionsAt an age of around 12 years, children with FHR-BP display enhanced neural sensitivity to change detection of duration deviants, while FHR-SZ showed a normal response pattern. Longitudinal recordings in high-risk children during adolescence are required to elucidate the temporal trajectories of MMN and P3a responses and how they relate to the emergence of first clinical symptoms in SZ and BP.

The effect of memantine on cortical network function in frontotemporal lobar degeneration is conditional on baseline GABA physiology

AbstractBackgroundFrontotemporal lobar degeneration (FTLD) is associated with deficits to GABA and glutamatergic neurotransmitters, particularly in the frontal cortex. While targeting GABAergic systems has shown to restore frontotemporal deficits in FTLD, little is known whether pharmacological probes of glutamatergic functioning have similar effects in these circuits.MethodTwenty participants with a FTLD‐associated syndrome (11 with PSP, 9 with bvFTD) and 20 healthy‐controls undertook two magnetoencephalography (MEG) sessions with a roving auditory oddball paradigm assessing frontotemporal change detection: (1) session on placebo and (2) after 10mg of oral memantine, which aims to blocks glutamatergic ecotoxicity. The mean amplitude of MEG “mismatch negativity” responses (MMN; standard‐deviants, 125‐175ms) was calculated across gradiometer sensors and for bilateral frontotemporal sources. Glutamate and GABA levels were measured using 7T proton magnetic resonance spectroscopy of the right inferior frontal gyrus (IFG). Frequentist and Bayesian ANOVAs assessed the differential mean MMN responses between controls and patients across placebo and drug conditions. Evoked difference waveforms (standard‐deviants) across the peristimulus time‐window were analysed using random field theory (RFT) (crit p=0.05, FWER) for the interaction effects of interest (i.e. drug session x group and drug x MRS levels).ResultPatients and controls did not demonstrate differential mean MMN amplitudes on placebo at the average‐sensor (p=0.95) or source‐level (p>0.27) (BF10=0.3‐0.5). Across sensors, only controls exhibited a differential drug‐dependent MMN, reflected by a steeper rebound of difference waveforms between 206‐288ms on memantine (Fig 1A; pFWER=0.026, cluster‐level). However, no interaction was found for mean MMNs (p>0.053). Notably, RFT (Fig 1B) and linear mixed models (Fig 1C) identified that greater GABA levels in patients are significantly associated with stronger MMN responses in right‐hemisphere areas under memantine. Glutamate levels did not moderate the mean MMN response to memantine (p>0.065).ConclusionOverall, we show that targeting glutamatergic systems may not lead to a restoration of frontotemporal physiology across patients. However, the effects of memantine are conditional on patient's baseline GABA, suggesting a critical balance between glutamatergic and GABA physiology that may underlie the large‐scale neural deficits in FTLD.

The mismatch negativity responses of individuals with tinnitus with normal extended high-frequency hearing-is it possible to use mismatch negativity in the evaluation of tinnitus?

This study uses the multi-feature paradigm to compare the MMN responses of individuals with normal hearing thresholds, including the high frequencies with and without tinnitus. Sixteen subjects with chronic subjective idiopathic tinnitus and twenty matched healthy controls were included in the study. Participants with hearing thresholds (0.125-16kHz) less than 20dB HL and MoCA test scores above 21 were included in the study. MMN responses and topographical maps of the responses resulting from the multi-feature MMN paradigm were recorded from 22 surface scalp electrodes. Amplitude and latency parameters of the MMN responses of five different deviants, consisting of frequency, intensity, duration, location, and silent gap, were compared between the two groups. The amplitudes of MMN responses were lower in the tinnitus group than in the control group at Fz electrode for all deviant types. At the same time, there was no difference between the groups for MMN latencies and, no correlation was found between THI and MMN. According to our results, the MMN might indicate a possible impairment in pre-attentive and automatic central auditory processing for chronic tinnitus patients. Since MMN responses in the tinnitus group differ from those of healthy individuals, it might be used as a reference for evaluating the central auditory pathways of tinnitus patients.

Neurophysiology of non-native sound discrimination: Evidence from German vowels and consonants in successive French–German bilinguals using an MMN oddball paradigm

Abstract The present electroencephalographical multi-speaker MMN oddball experiment was designed to study the phonological processing of German native and non-native speech sounds. Precisely, we focused on the perception of German /ɪ-iː/, /ɛ-ɛː/, /a-aː/ and the fricatives [ʃ] and [ç] in German natives (GG) and French learners of German (FG). As expected, our results showed that GG were able to discriminate all the critical vowel contrasts. In contrast, FG, despite their high L2 proficiency level, were only marginally sensitive to vowel length variations. Finally, neither GG nor FG discriminated the opposition between [ʃ] and [ç], as revealed by the absence of MMN response. This latter finding was interpreted in terms of low perceptual salience. Taken together, the present findings lend partial support to the Perceptual Assimilation Model for late bilinguals (PAM-L2) for speech perception of non-native phonological contrasts.

Violation of rhythmic expectancies can elicit late frontal gamma activity nested in theta oscillations.

Rhythm processing involves building expectations according to the hierarchical temporal structure of auditory events. Although rhythm processing has been addressed in the context of predictive coding, the properties of the oscillatory response in different cortical areas are still not clear. We explored the oscillatory properties of the neural response to rhythmic incongruence and the cross‐frequency coupling between multiple frequencies to further investigate the mechanisms underlying rhythm perception. We designed an experiment to investigate the neural response to rhythmic deviations in which the tone either arrived earlier than expected or the tone in the same metrical position was omitted. These two manipulations modulate the rhythmic structure differently, with the former creating a larger violation of the general structure of the musical stimulus than the latter. Both deviations resulted in an MMN response, whereas only the rhythmic deviant resulted in a subsequent P3a. Rhythmic deviants due to the early occurrence of a tone, but not omission deviants, seemed to elicit a late high gamma response (60–80 Hz) at the end of the P3a over the left frontal region, which, interestingly, correlated with the P3a amplitude over the same region and was also nested in theta oscillations. The timing of the elicited high‐frequency gamma oscillations related to rhythmic deviation suggests that it might be related to the update of the predictive neural model, corresponding to the temporal structure of the events in higher‐level cortical areas.

Sources of the frontocentral mismatch negativity and P3a responses in schizophrenia patients and healthy comparison subjects

BackgroundMismatch negativity (MMN) and P3a are event-related potential measures of early auditory information processing that are increasingly used as translational biomarkers in the development of treatments for neuropsychiatric disorders. These responses are reduced in schizophrenia patients over the frontocentral scalp electrodes and are associated with important domains of cognitive and psychosocial functioning. While MMN and P3a responses are generated by a dynamic network of cortical sources distributed across the temporal and frontal brain regions, it is not clear how these sources independently contribute to MMN and P3a at the primary frontocentral scalp electrode or to abnormalities observed in schizophrenia. This study aimed to determine the independent source contributions and characterize the magnitude of impairment in source-level MMN and P3a responses in schizophrenia patients. MethodsA novel method was applied to back-project the contributions of 11 independent cortical source components to Fz, the primary scalp sensor that is used in clinical studies, in n = 589 schizophrenia patients and n = 449 healthy comparison subjects. ResultsThe groups showed comparable individual source contributions underlying both MMN and P3a responses at Fz. Source-level responses revealed an increasing magnitude of impairment in schizophrenia patients from the temporal to more frontal sources. ConclusionsSchizophrenia patients have a normal architecture of source contributions that are accompanied by widespread abnormalities in source resolved mismatch and P3a responses, with more prominent deficits detected from the frontal sources. Quantification of source contributions and source-level responses accelerates clarification of the neural networks underlying MMN reduction at Fz in schizophrenia patients.

Musical Expertise Facilitates Dissonance Detection On Behavioral, Not On Early Sensory Level

Consonance and dissonance are basic phenomena in the perception of chords that can be discriminated very early in sensory processing. Musical expertise has been shown to facilitate neural processing of various musical stimuli, but it is unclear whether this applies to detecting consonance and dissonance. Our study aimed to determine if sensitivity to increasing levels of dissonance differs between musicians and nonmusicians, using a combination of neural (electroencephalographic mismatch negativity, MMN) and behavioral measurements (conscious discrimination). Furthermore, we wanted to see if focusing attention to the sounds modulated the neural processing. We used chords comprised of either highly consonant or highly dissonant intervals and further manipulated the degree of dissonance to create two levels of dissonant chords. Both groups discriminated dissonant chords from consonant ones neurally and behaviorally. The magnitude of the MMN differed only marginally between the more dissonant and the less dissonant chords. The musicians outperformed the nonmusicians in the behavioral task. As the dissonant chords elicited MMN responses for both groups, sensory dissonance seems to be discriminated in an early sensory level, irrespective of musical expertise, and the facilitating effects of musicianship for this discrimination may arise in later stages of auditory processing, appearing only in the behavioral auditory task.

Effect of Motion Trajectory on the Lateralization of Auditory Evoked Responses

Processing of acoustic space in the human auditory system implicates the interaction of the left and right hemispheres of the brain. In this study, we investigated the influence of the position and motion direction of sound stimuli on the amplitude and latency of N1, P2, MMN, and P3a components of auditory evoked potentials in the left and right brain hemispheres. The data suggest that functional asymmetry of the N1P2 complex and difference waveforms can be described as weak contralateral dominance. Deviants moving from the lateral positions evoked later P3a components than those moving from the midline, which is consistent with the concept of higher localization accuracy in the frontal part of the acoustic space. The motion direction affected the MMN and P3a latency: the centrifugal deviants produced earlier MMN and P3a responses than the centripetal deviants. This could result from a stronger orienting reaction caused by stimuli moving from the center towards the periphery as compared with the opposite direction.

Electrophysiological evidence of preserved hearing at the end of life

This study attempts to answer the question: “Is hearing the last to go?” We present evidence of hearing among unresponsive actively dying hospice patients. Individual ERP (MMN, P3a, and P3b) responses to deviations in auditory patterns are reported for conscious young, healthy control participants, as well as for hospice patients, both when the latter were conscious, and again when they became unresponsive to their environment. Whereas the MMN (and perhaps too the P3a) is considered an automatic response to auditory irregularities, the P3b is associated with conscious detection of oddball targets. All control participants, and most responsive hospice patients, evidenced a “local” effect (either a MMN, a P3a, or both) and some a “global” effect (P3b) to deviations in tone, or deviations in auditory pattern. Importantly, most unresponsive patients showed evidence of MMN responses to tone changes, and some showed a P3a or P3b response to either tone or pattern changes. Thus, their auditory systems were responding similarly to those of young, healthy controls just hours from end of life. Hearing may indeed be one of the last senses to lose function as humans die.

Auditory Processing of Speech and Tones in Children With Tuberous Sclerosis Complex.

Individuals with Tuberous Sclerosis Complex (TSC) have atypical white matter integrity and neural connectivity in the brain, including language pathways. To explore functional activity associated with auditory and language processing in individuals with TSC, we used electroencephalography (EEG) to examine basic auditory correlates of detection (P1, N2, N4) and discrimination (mismatch negativity, MMN) of speech and non-speech stimuli for children with TSC and age- and sex-matched typically developing (TD) children. Children with TSC (TSC group) and without TSC (typically developing, TD group) participated in an auditory MMN paradigm containing two blocks of vowels (/a/and/u/) and two blocks of tones (800 Hz and 400 Hz). Continuous EEG data were collected. Multivariate pattern analysis (MVPA) was used to explore functional specificity of neural auditory processing. Speech-specific P1, N2, and N4 waveform components of the auditory evoked potential (AEP) were compared, and the mismatch response was calculated for both speech and tones. MVPA showed that the TD group, but not the TSC group, demonstrated above-chance pairwise decoding between speech and tones. The AEP component analysis suggested that while the TD group had an increased P1 amplitude in response to vowels compared to tones, the TSC group did not show this enhanced response to vowels. Additionally, the TD group had a greater N2 amplitude in response to vowels, but not tones, compared to the TSC group. The TSC group also demonstrated a longer N4 latency to vowels compared to tones, which was not seen in the TD group. No group differences were observed in the MMN response. In this study we identified features of the auditory response to speech sounds, but not acoustically matched tones, which differentiate children with TSC from TD children.

Mismatch negativity to different deviant changes in autism spectrum disorders: A meta-analysis

ObjectiveMismatch negativity (MMN) has been continuously used to evaluate the functional integrity of central auditory processing. However, it still remains inconclusive whether patients with autism spectrum disorder (ASD) demonstrate reduced MMN responses in all deviant types. MethodsTo reconcile the previous controversial findings, we performed a meta-analysis of peer-reviewed MMN articles concerning ASD. The potential moderators regarding different deviant types, diagnosis, and age on the effect sizes (Hedges’ g) were also assessed. ResultsCompared to the controls, ASD patients showed reduced MMN amplitudes (g = −0.37, p = 0.001) and prolonged latencies (g = −0.33, p = 0.041) in response to speech-sound deviants. Children/adolescents with ASD manifested reduced MMN amplitudes in response to tone-duration deviants (g = −0.46, p = 0.014). Furthermore, the results showed significantly shortened MMN latencies to tone-frequency deviants in patients with autism (g = 0.29, p = 0.038) and, in contrast, prolonged MMN latencies (g = −0.74, p = 0.001) in patients with Asperger syndrome. ConclusionMMN deficits are robust in ASD patients, suggesting an altered central ability in auditory discrimination. SignificanceMMN alterations were displayed in different profiles with respect to frequency, duration and phoneme changes.

Action Intention-based and Stimulus Regularity-based Predictions: Same or Different?

We act on the environment to produce desired effects, but we also adapt to the environmental demands by learning what to expect next, based on experience: How do action-based predictions and sensory predictions relate to each other? We explore this by implementing a self-generation oddball paradigm, where participants performed random sequences of left and right button presses to produce frequent standard and rare deviant tones. By manipulating the action-tone association as well as the likelihood of a button press over the other one, we compare ERP effects evoked by the intention to produce a specific tone, tone regularity, and both intention and regularity. We show that the N1b and Tb components of the N1 response are modulated by violations of tone regularity only. However, violations of action intention as well as of regularity elicit MMN responses, which occur similarly in all three conditions. Regardless of whether the predictions at sensory levels were based on either intention, regularity, or both, the tone deviance was further and equally well detected at hierarchically higher processing level, as reflected in similar P3a effects between conditions. We did not observe additive prediction errors when intention and regularity were violated concurrently, suggesting the two integrate despite presumably having independent generators. Even though they are often discussed as individual prediction sources in the literature, this study represents to our knowledge the first to directly compare them. Finally, these results show how, in the context of action, our brain can easily switch between top-down intention-based expectations and bottom-up regularity cues to efficiently predict future events.

Attenuated mismatch negativity in patients with first-episode antipsychotic-naive schizophrenia using a source-resolved method.

BackgroundMismatch negativity (MMN) is a measure of pre-attentive auditory information processing related to change detection. Traditional scalp-level EEG methods consistently find attenuated MMN in patients with chronic but not first-episode schizophrenia. In the current paper, we use a source-resolved method to assess MMN and hypothesize that more subtle changes can be identified with this analysis method.MethodFifty-six first-episode antipsychotic-naïve schizophrenia (FEANS) patients (31 males, 25 females, mean age 24.6) and 64 matched controls (37 males, 27 females, mean age 24.8) were assessed for duration-, frequency- and combined-type MMN and P3a as well as 4 clinical, 3 cognitive and 3 psychopathological measures. To evaluate and correlate MMN at source-level, independent component analysis (ICA) was applied to the continuous EEG data to derive equivalent current dipoles which were clustered into 19 clusters based on cortical location.ResultsNo scalp channel group MMN or P3a amplitude differences were found. Of the localized clusters, several were in or near brain areas previously suggested to be involved in the MMN response, including frontal and anterior cingulate cortices and superior temporal and inferior frontal gyri. For duration deviants, MMN was attenuated at the right superior temporal gyrus in patients compared to healthy controls (p = 0.01), as was P3a at the superior frontal cortex (p = 0.01). No individual patient correlations with clinical, cognitive, or psychopathological measures survived correction for multiple comparisons.ConclusionAttenuated source-localized MMN and P3a peak contributions can be identified in FEANS patients using a method based on independent component analysis (ICA). This indicates that deficits in pre-attentive auditory information processing are present at this early stage of schizophrenia and are not the result of disease chronicity or medication. This is to our knowledge the first study on FEANS patients using this more detailed method.