Prosodic discrimination in patients with schizophrenia

Syntactic and affective prosody recognition: Schizophrenia vs. Autism spectrum disorders

Patients with a recent diagnosis of schizophrenia and individuals receiving a diagnosis of autism spectrum disorder without accompanying intellectual impairment (ASD w/o intellectual impairment) during their adulthood share several clinical characteristics. Exploring under-investigated aspects of these two clinical conditions may shed light on their possible connection and facilitate differential diagnosis at very early stages. To this end, we explored the ability of 15 adults with a recent diagnosis of schizophrenia, 15 individuals diagnosed with ASD w/o intellectual impairment as adults, and 15 healthy adults to resolve sentence ambiguities with the use of syntactic prosody, and to decode happiness, anger, sadness, surprise, fear, and neutrality based on affective prosody. Results revealed intact perception of syntactic prosody in adults with schizophrenia, but impaired affective prosody recognition, which could be attributed, however, to emotion processing difficulties overall. On the other hand, individuals with ASD w/o intellectual impairment were impaired on prosody comprehension per se, as evidenced in the most challenging conditions, namely the subject-reading condition and the emotion of surprise. The differences in prosody comprehension ability between the two clinical conditions may serve as an indicator, among other signs, during the diagnostic evaluation.

Speech Prosody as a Bridge Between Psychopathology and Linguistics: The Case of the Schizophrenia Spectrum

Patients with schizophrenia spectrum disorders experience severe difficulties in interpersonal communication, as described by traditional psychopathology and current research on social cognition. From a linguistic perspective, pragmatic abilities are crucial for successful communication. Empirical studies have shown that these abilities are significantly impaired in this group of patients. Prosody, the tone of voice with which words and sentences are pronounced, is one of the most important carriers of pragmatic meaning and can serve a range of functions from linguistic to emotional ones. Most of the existing literature on prosody of patients with schizophrenia spectrum disorders focuses on the expression of emotion, generally showing significant impairments. By contrast, the use of non-emotional prosody in these patients is scarcely investigated. In this paper, we first present a linguistic model to classify prosodic functions. Second, we discuss existing studies on the use of non-emotional prosody in these patients, providing an overview of the state of the art. Third, we delineate possible future lines of research in this field, also taking into account some classical psychopathological assumptions, for both diagnostic and therapeutic purposes.

Mismatch Negativity to Threatening Voices Associated with Positive Symptoms in Schizophrenia

Although the general consensus holds that emotional perception is impaired in patients with schizophrenia, the extent to which neural processing of emotional voices is altered in schizophrenia remains to be determined. This study enrolled 30 patients with chronic schizophrenia and 30 controls and measured their mismatch negativity (MMN), a component of auditory event-related potentials (ERP). In a passive oddball paradigm, happily or angrily spoken deviant syllables dada were randomly presented within a train of emotionally neutral standard syllables. Results showed that MMN in response to angry syllables and angry-derived non-vocal sounds was significantly decreased in individuals with schizophrenia. P3a to angry syllables showed stronger amplitudes but longer latencies. Weaker MMN amplitudes were associated with more positive symptoms of schizophrenia. Receiver operator characteristic analysis revealed that angry MMN, angry-derived MMN, and angry P3a could help predict whether someone had received a clinical diagnosis of schizophrenia. The findings suggested general impairments of voice perception and acoustic discrimination in patients with chronic schizophrenia. The emotional salience processing of voices showed an atypical fashion at the preattentive level, being associated with positive symptoms in schizophrenia.

A Cognitive Neuroscience View of Voice-Processing Abnormalities in Schizophrenia: A Window into Auditory Verbal Hallucinations?

Auditory verbal hallucinations (AVH) are a core symptom of schizophrenia. Like "real" voices, AVH carry a rich amount of linguistic and paralinguistic cues that convey not only speech, but also affect and identity, information. Disturbed processing of voice identity, affective, and speech information has been reported in patients with schizophrenia. More recent evidence has suggested a link between voice-processing abnormalities and specific clinical symptoms of schizophrenia, especially AVH. It is still not well understood, however, to what extent these dimensions are impaired and how abnormalities in these processes might contribute to AVH. In this review, we consider behavioral, neuroimaging, and electrophysiological data to investigate the speech, identity, and affective dimensions of voice processing in schizophrenia, and we discuss how abnormalities in these processes might help to elucidate the mechanisms underlying specific phenomenological features of AVH. Schizophrenia patients exhibit behavioral and neural disturbances in the three dimensions of voice processing. Evidence suggesting a role of dysfunctional voice processing in AVH seems to be stronger for the identity and speech dimensions than for the affective domain.

Prosodic Structure as a Parallel to Musical Structure

What structural properties do language and music share? Although early speculation identified a wide variety of possibilities, the literature has largely focused on the parallels between musical structure and syntactic structure. Here, we argue that parallels between musical structure and prosodic structure deserve more attention. We review the evidence for a link between musical and prosodic structure and find it to be strong. In fact, certain elements of prosodic structure may provide a parsimonious comparison with musical structure without sacrificing empirical findings related to the parallels between language and music. We then develop several predictions related to such a hypothesis.

Can the Acoustic Analysis of Expressive Prosody Discriminate Schizophrenia?

Emotional states, attitudes and intentions are often conveyed by modulations in the tone of voice. Impaired recognition of emotions from a tone of voice (receptive prosody) has been described as characteristic symptoms of schizophrenia. However, the ability to express non-verbal information in speech (expressive prosody) has been understudied. This paper describes a useful technique for quantifying the degree of expressive prosody deficits in schizophrenia, using a semi-automatic method, and evaluates this method's ability to discriminate between patient and control groups. Forty-five medicated patients with a diagnosis of schizophrenia were matched with thirty-five healthy comparison subjects. Production of expressive prosodic speech was analyzed using variation in fundamental frequency (F0) measures on an emotionally neutral reading task. Results revealed that patients with schizophrenia exhibited significantly more pauses (p < .001), were slower (p < .001), and showed less pitch variability in speech (p < .05) and fewer variations in syllable timing (p < .001) than control subjects. These features have been associated with «flat» speech prosody. Signal processing algorithms applied to speech were shown to be capable of discriminating between patients and controls with an accuracy of 93.8%. These speech parameters may have a diagnostic and prognosis value and therefore could be used as a dependent measure in clinical trials.

Amusia and cognitive deficits in schizophrenia: is there a relationship?

The current study explored the music perception ability of individuals diagnosed with schizophrenia and its relationship with other cognitive abilities and psychotic symptom severity. The persons with schizophrenia performed significantly worse than the control group on the Montreal Battery of Evaluation of Amusia (MBEA) (p<0.001). The music perception ability of persons with schizophrenia was related to other cognitive abilities (attention, verbal memory, spatial memory, and executive function) and the severity of psychotic symptoms.

Impaired musical ability in people with schizophrenia

BACKGROUND

Assessment of the musical ability of people with schizophrenia has attracted little interest despite the diverse and substantive findings of impairments in sound perception and processing and the therapeutic effect of music in people with the illness. The present study investigated the musical ability of people with schizophrenia and the association with psychiatric symptoms and cognition.

METHODS

We recruited patients with chronic schizophrenia and healthy controls for participation in our study. To measure musical ability and cognitive function, we used the Montreal Battery of Evaluation of Amusia (MBEA) and the Brief Assessment of Cognition in Schizophrenia (BACS). We carried out a mediation analysis to investigate a possible pathway to a deficit in musical ability.

RESULTS

We enrolled 50 patients and 58 controls in the study. The MBEA global score in patients with schizophrenia was significantly lower than that in controls (p < 0.001), and was strongly associated with both the composite cognitive function score (r = 0.645, p < 0.001) and the negative symptom score (r = -0.504, p < 0.001). Further analyses revealed direct and indirect effects of negative symptoms on musical ability. The indirect effects were mediated through cognitive impairment.

LIMITATIONS

The relatively small sample size did not permit full evaluation of the possible effects of age, sex, education, medication and cultural influences on the results.

CONCLUSION

Examining the associations between musical deficits, negative symptoms and cognitive imapirment in patients with schizophrenia may identify shared biological mechanisms.

Is Central Auditory Processing Disorder Present in Psychosis?

Purpose

The scope of this study was to trace central auditory processing issues in patients with first-episode psychosis using a psychoacoustic test battery approach.

Method

Patients ( n = 17) and volunteer control subjects ( n = 17) with no personal or family history of schizophrenia were included in the study on the basis of normal hearing sensitivity. The authors implemented a central auditory processing battery consisting of monaural and binaural tests with verbal and nonverbal stimuli.

Results

Perceptual deficits in both nonverbal and verbal auditory stimuli are reported in this study, with temporal central auditory processing deficits and a mean left-ear advantage documented in the patient group.

Conclusion

This study points to the possibility of the existence of central auditory processing deficits in first-episode psychosis leading to schizophrenia. Audiologists should be aware of the psychiatric research pointing to enhanced verbal memory as a result of auditory training, linking bottom-up remediation with top-down improvement.

Emotional processing during speech communication and positive symptoms in schizophrenia

AIMS

The recognition of emotion is often impaired in patients with schizophrenia. The relationship of this deficit with symptoms of psychosis remains unclear. In the current study, we investigated the relationship between emotional processing and positive psychotic symptoms in schizophrenia.

METHODS

Twenty-eight patients with schizophrenia and 37 healthy participants were included in the study. They were instructed to listen to a set of sentences and judge whether the emotional valence expressed verbally and that expressed by affective prosody were congruous or incongruous.

RESULTS

Overall, the patients with schizophrenia had more inaccurate responses than the healthy participants and the poor performance was prominent when the patients processed affectively negative scenarios. The percentage of accurate responses negatively correlated with the severity of positive symptoms when the scenarios and/or the affective prosody had a negative valence.

CONCLUSION

Patients with schizophrenia appear to have impaired function in the processing of negative verbal information. Impaired processing of negative verbal and prosodic information seems to be associated with positive symptoms in schizophrenia.

Auditory processing and hallucinations in schizophrenia

The aim of this study was to investigate whether deficits in auditory processing are associated with auditory hallucinations in patients with schizophrenia. It was hypothesised that individuals with a diagnosis of schizophrenia would demonstrate deficits in processing the spectral and temporal aspects of sound and that such deficits would be more pronounced in patients with a history of auditory hallucinations (hallucinators) than those without such a history (non-hallucinators). A community sample meeting clinical criteria for schizophrenia or schizoaffective disorder (19 hallucinators, 15 non-hallucinators) and a matched healthy control group (n=17) completed a broad range of auditory processing tasks involving pitch discrimination of modulated (temporal) and unmodulated (spectral) pure tones, auditory streaming and affective prosodic identification, as well as measures assessing current psychiatric symptoms. In all experimental tasks patients were impaired compared to controls. Specifically hallucinators performed worse than non-hallucinators and controls for pitch discrimination of unmodulated tones and auditory streaming, and both hallucinators and non-hallucinators performed significantly worse than controls for discrimination of modulated tones and affective prosody. These findings suggest that impaired temporal processing may contribute to general difficulties identifying affective speech prosody in patients with schizophrenia, while spectral processing deficits may specifically compromise melodic streaming in hallucinators, which combined with deficits in temporal processing, contribute to the experience of auditory hallucinations.

An examination of auditory processing and affective prosody in relatives of patients with auditory hallucinations

Research on auditory verbal hallucinations (AVHs) indicates that AVH schizophrenia patients show greater abnormalities on tasks requiring recognition of affective prosody (AP) than non-AVH patients. Detecting AP requires accurate perception of manipulations in pitch, amplitude and duration. Schizophrenia patients with AVHs also experience difficulty detecting these acoustic manipulations; with a number of theorists speculating that difficulties in pitch, amplitude and duration discrimination underlie AP abnormalities. This study examined whether both AP and these aspects of auditory processing are also impaired in first degree relatives of persons with AVHs. It also examined whether pitch, amplitude and duration discrimination were related to AP, and to hallucination proneness. Unaffected relatives of AVH schizophrenia patients (N = 19) and matched healthy controls (N = 33) were compared using tone discrimination tasks, an AP task, and clinical measures. Relatives were slower at identifying emotions on the AP task (p = 0.002), with secondary analysis showing this was especially so for happy (p = 0.014) and neutral (p = 0.001) sentences. There was a significant interaction effect for pitch between tone deviation level and group (p = 0.019), and relatives performed worse than controls on amplitude discrimination and duration discrimination. AP performance for happy and neutral sentences was significantly correlated with amplitude perception. Lastly, AVH proneness in the entire sample was significantly correlated with pitch discrimination (r = 0.44) and pitch perception was shown to predict AVH proneness in the sample (p = 0.005). These results suggest basic impairments in auditory processing are present in relatives of AVH patients; they potentially underlie processing speed in AP tasks, and predict AVH proneness. This indicates auditory processing deficits may be a core feature of AVHs in schizophrenia, and are worthy of further study as a potential endophenotype for AVHs.

Mechanisms Underlying Auditory Hallucinations-Understanding Perception without Stimulus

Auditory verbal hallucinations (AVH) are a common phenomenon, occurring in the “healthy” population as well as in several mental illnesses, most notably schizophrenia. Current thinking supports a spectrum conceptualisation of AVH: several neurocognitive hypotheses of AVH have been proposed, including the “feed-forward” model of failure to provide appropriate information to somatosensory cortices so that stimuli appear unbidden, and an “aberrant memory model” implicating deficient memory processes. Neuroimaging and connectivity studies are in broad agreement with these with a general dysconnectivity between frontotemporal regions involved in language, memory and salience properties. Disappointingly many AVH remain resistant to standard treatments and persist for many years. There is a need to develop novel therapies to augment existing pharmacological and psychological therapies: transcranial magnetic stimulation has emerged as a potential treatment, though more recent clinical data has been less encouraging. Our understanding of AVH remains incomplete though much progress has been made in recent years. We herein provide a broad overview and review of this.

Prosody recognition and audiovisual emotion matching in schizophrenia: the contribution of cognition and psychopathology

This study aimed to evaluate the ability to decode emotion in the auditory and audiovisual modality in a group of patients with schizophrenia, and to explore the role of cognition and psychopathology in affecting these emotion recognition abilities. Ninety-four outpatients in a stable phase and 51 healthy subjects were recruited. Patients were assessed through a psychiatric evaluation and a wide neuropsychological battery. All subjects completed the comprehensive affect testing system (CATS), a group of computerized tests designed to evaluate emotion perception abilities. With respect to the controls, patients were not impaired in the CATS tasks involving discrimination of nonemotional prosody, naming of emotional stimuli expressed by voice and judging the emotional content of a sentence, whereas they showed a specific impairment in decoding emotion in a conflicting auditory condition and in the multichannel modality. Prosody impairment was affected by executive functions, attention and negative symptoms, while deficit in multisensory emotion recognition was affected by executive functions and negative symptoms. These emotion recognition deficits, rather than being associated purely with emotion perception disturbances in schizophrenia, are affected by core symptoms of the illness.

Relationship between auditory processing and affective prosody in schizophrenia

Patients with schizophrenia have well-established deficits in their ability to identify emotion from facial expression and tone of voice. In the visual modality, there is strong evidence that basic processing deficits contribute to impaired facial affect recognition in schizophrenia. However, few studies have examined the auditory modality for mechanisms underlying affective prosody identification. In this study, we explored links between different stages of auditory processing, using event-related potentials (ERPs), and affective prosody detection in schizophrenia. Thirty-six schizophrenia patients and 18 healthy control subjects received tasks of affective prosody, facial emotion identification, and tone matching, as well as two auditory oddball paradigms, one passive for mismatch negativity (MMN) and one active for P300. Patients had significantly reduced MMN and P300 amplitudes, impaired auditory and visual emotion recognition, and poorer tone matching performance, relative to healthy controls. Correlations between ERP and behavioral measures within the patient group revealed significant associations between affective prosody recognition and both MMN and P300 amplitudes. These relationships were modality specific, as MMN and P300 did not correlate with facial emotion recognition. The two ERP waves accounted for 49% of the variance in affective prosody in a regression analysis. Our results support previous suggestions of a relationship between basic auditory processing abnormalities and affective prosody dysfunction in schizophrenia, and indicate that both relatively automatic pre-attentive processes (MMN) and later attention-dependent processes (P300) are involved with accurate auditory emotion identification. These findings provide support for bottom-up (e.g., perceptually based) cognitive remediation approaches.

Voice identity recognition failure in patients with schizophrenia

Cognitive models propose that auditory verbal hallucinations arise through inner speech misidentification. However, such models cannot explain why the voices in hallucinations often have identities different from the hearer. This study investigated whether a general voice identity recognition difficulty might be present in schizophrenia and related to auditory verbal hallucinations. Twenty-five schizophrenia patients and 13 healthy controls were tested on recognition of famous voices. Signal detection theory was used to calculate perceptual sensitivity and response criterion measures. Schizophrenia patients obtained fewer hits and had lower perceptual sensitivity to detect famous voices than healthy controls did. There were no differences between groups in false alarm rate or response criterion. A symptom-based analysis demonstrated that especially those patients with auditory verbal hallucinations performed poorly in the task. The results indicate that patients with hallucinations are impaired at voice identity recognition because of decreased sensitivity, which may result in inner speech misidentification.

It's not what you say but the way that you say it: an fMRI study of differential lexical and non-lexical prosodic pitch processing

BACKGROUND

This study aims to identify the neural substrate involved in prosodic pitch processing. Functional magnetic resonance imaging was used to test the premise that prosody pitch processing is primarily subserved by the right cortical hemisphere.Two experimental paradigms were used, firstly pairs of spoken sentences, where the only variation was a single internal phrase pitch change, and secondly, a matched condition utilizing pitch changes within analogous tone-sequence phrases. This removed the potential confounder of lexical evaluation. fMRI images were obtained using these paradigms.

RESULTS

Activation was significantly greater within the right frontal and temporal cortices during the tone-sequence stimuli relative to the sentence stimuli.

CONCLUSION

This study showed that pitch changes, stripped of lexical information, are mainly processed by the right cerebral hemisphere, whilst the processing of analogous, matched, lexical pitch change is preferentially left sided. These findings, showing hemispherical differentiation of processing based on stimulus complexity, are in accord with a 'task dependent' hypothesis of pitch processing.

Not pitch perfect: sensory contributions to affective communication impairment in schizophrenia

BACKGROUND

Schizophrenia patients have vocal affect (prosody) deficits that are treatment resistant and associated with negative symptoms and poor outcome. The neural correlates of this dysfunction are unclear. Prior study has suggested that schizophrenia vocal affect perception deficits stem from an inability to use acoustic cues, notably pitch, in decoding emotion.

METHODS

Functional magnetic resonance imaging was performed in 24 schizophrenia patients and 28 healthy control subjects, during the performance of a four-choice (happiness, fear, anger, neutral) vocal affect identification task in which items for each emotion varied parametrically in affective salient acoustic cue levels.

RESULTS

We observed that parametric increases in cue levels in schizophrenia failed to produce the same identification rate increases as in control subjects. These deficits correlated with diminished reciprocal activation changes in superior temporal and inferior frontal gyri and reduced temporo-frontal connectivity. Task activation also correlated with independent measures of pitch perception and negative symptom severity.

CONCLUSIONS

These findings illustrate the interplay between sensory and higher-order cognitive dysfunction in schizophrenia. Sensory contributions to vocal affect deficits also suggest that this neurobehavioral marker could be targeted by pharmacological or behavioral remediation of acoustic feature discrimination.

Decision making on ambiguous stimuli such as prosody by subjects suffering from paranoid schizophrenia, alcohol dependence, and without psychiatric diagnosis

The aim of this study is the empirical verification of the Bayesian approach applied to the description of the decision-making process with regard to prosodic stimuli in different psychopathological states. Using the Bayesian formalism, the interpretation of a disturbance in internal representation of the contextual information in schizophrenia was given. The results obtained satisfied the formula derived from Bayes' theorem in all tested except a schizophrenic group. Results were interpreted as reflecting cognitive flexibility, and discussed in the context of social adaptation. Although the investigation was based on psychopathological grounds, the results may be applied to the functioning of working memory in general.

The role of the insula in schizophrenia

Involvement of the insular cortex is a common finding in neuroanatomical studies of schizophrenia, yet its contribution to disease pathology remains unknown. This review describes the normal function of the insula and examines pathology of this region in schizophrenia. The insula is a cortical structure with extensive connections to many areas of the cortex and limbic system. It integrates external sensory input with the limbic system and is integral to the awareness of the body's state (interoception). Many deficits observed in schizophrenia involve these functions and may relate to insula pathology. Furthermore, reports describing deficits caused by lesions of the insula parallel deficits observed in schizophrenia. Examples of insula-related functions that are altered in schizophrenia include the processing of both visual and auditory emotional information, pain, and neuronal representations of the self. The last of these functions, processing representations of the self, plays a key role in discriminating between self-generated and external information, suggesting that insula dysfunction may contribute to hallucinations, a cardinal feature of schizophrenia.

The cognitive neuropsychology of auditory hallucinations: a parallel auditory pathways framework

Auditory hallucinations are generally defined as false perceptions. Recent developments in auditory neuroscience have rapidly increased our understanding of normal auditory perception revealing (partially) separate pathways for the identification ("what") and localization ("where") of auditory objects. The current review offers a reexamination of the nature of auditory hallucinations in schizophrenia using this object-based framework. First, the structural and functional organization of auditory what and where pathways is briefly described. Then, using recent functional neuroimaging data from healthy subjects and patients with schizophrenia, key phenomenological features of hallucinations are linked to abnormal processing both within and between these pathways. Finally, current cognitive explanations of hallucinations, based on intrusive cognitions and impaired source memory, are briefly outlined and set within this framework to provide an integrated cognitive neuropsychological model of auditory hallucinations.

Getting the cue: sensory contributions to auditory emotion recognition impairments in schizophrenia

Individuals with schizophrenia show reliable deficits in the ability to recognize emotions from vocal expressions. Here, we examined emotion recognition ability in 23 schizophrenia patients relative to 17 healthy controls using a stimulus battery with well-characterized acoustic features. We further evaluated performance deficits relative to ancillary assessments of underlying pitch perception abilities. As predicted, patients showed reduced emotion recognition ability across a range of emotions, which correlated with impaired basic tone matching abilities. Emotion identification deficits were strongly related to pitch-based acoustic cues such as mean and variability of fundamental frequency. Whereas healthy subjects' performance varied as a function of the relative presence or absence of these cues, with higher cue levels leading to enhanced performance, schizophrenia patients showed significantly less variation in performance as a function of cue level. In contrast to pitch-based cues, both groups showed equivalent variation in performance as a function of intensity-based cues. Finally, patients were less able than controls to differentiate between expressions with high and low emotion intensity, and this deficit was also correlated with impaired tone matching ability. Both emotion identification and intensity rating deficits were unrelated to valence of intended emotions. Deficits in both auditory emotion identification and more basic perceptual abilities correlated with impaired functional outcome. Overall, these findings support the concept that auditory emotion identification deficits in schizophrenia reflect, at least in part, a relative inability to process critical acoustic characteristics of prosodic stimuli and that such deficits contribute to poor global outcome.

"It's Not What You Say, But How You Say it": A Reciprocal Temporo-frontal Network for Affective Prosody

Humans communicate emotion vocally by modulating acoustic cues such as pitch, intensity and voice quality. Research has documented how the relative presence or absence of such cues alters the likelihood of perceiving an emotion, but the neural underpinnings of acoustic cue-dependent emotion perception remain obscure. Using functional magnetic resonance imaging in 20 subjects we examined a reciprocal circuit consisting of superior temporal cortex, amygdala and inferior frontal gyrus that may underlie affective prosodic comprehension. Results showed that increased saliency of emotion-specific acoustic cues was associated with increased activation in superior temporal cortex [planum temporale (PT), posterior superior temporal gyrus (pSTG), and posterior superior middle gyrus (pMTG)] and amygdala, whereas decreased saliency of acoustic cues was associated with increased inferior frontal activity and temporo-frontal connectivity. These results suggest that sensory-integrative processing is facilitated when the acoustic signal is rich in affective information, yielding increased activation in temporal cortex and amygdala. Conversely, when the acoustic signal is ambiguous, greater evaluative processes are recruited, increasing activation in inferior frontal gyrus (IFG) and IFG STG connectivity. Auditory regions may thus integrate acoustic information with amygdala input to form emotion-specific representations, which are evaluated within inferior frontal regions.

The influence of emotion clarity on emotional prosody identification in paranoid schizophrenia

BACKGROUND

Identification of emotional facial expression and emotional prosody (i.e. speech melody) is often impaired in schizophrenia. For facial emotion identification, a recent study suggested that the relative deficit in schizophrenia is enhanced when the presented emotion is easier to recognize. It is unclear whether this effect is specific to face processing or part of a more general emotion recognition deficit.

METHOD

We used clarity-graded emotional prosodic stimuli without semantic content, and tested 25 in-patients with paranoid schizophrenia, 25 healthy control participants and 25 depressive in-patients on emotional prosody identification. Facial expression identification was used as a control task.

RESULTS

Patients with paranoid schizophrenia performed worse than both control groups in identifying emotional prosody, with no specific deficit in any individual emotion category. This deficit was present in high-clarity but not in low-clarity stimuli. Performance in facial control tasks was also impaired, with identification of emotional facial expression being a better predictor of emotional prosody identification than illness-related factors. Of those, negative symptoms emerged as the best predictor for emotional prosody identification.

CONCLUSIONS

This study suggests a general deficit in identifying high-clarity emotional cues. This finding is in line with the hypothesis that schizophrenia is characterized by high noise in internal representations and by increased fluctuations in cerebral networks.

Brain structural changes in schizophrenia patients with persistent hallucinations

Schizophrenia is characterised by the presence of a heterogeneous range of symptoms. Although there is a consensus regarding ventricular enlargement and regional grey matter deficits, the brain structural correlates of specific symptoms, such as auditory hallucinations, are not clearly defined. We used an automated voxel-wise analysis of dual-echo spin-echo MRI data from 28 patients with schizophrenia characterised by persistent hallucinations and 32 healthy controls. Patients demonstrated grey matter (GM) volume decrements in the insula bilaterally, and in the right superior temporal and fusiform gyri, and left inferior temporal gyrus. With the exception of the insula, these GM volume losses were correlated with severity of auditory hallucinations. GM excesses were observed in the right caudate nucleus and middle temporal gyrus. White matter deficits were observed adjacent to the left superior temporal gyrus, in the right internal capsule and inferior longitudinal fasciculus. These findings support the proposition that there are structural changes in the neural circuits underlying broader processing of affect-laden information in patients with schizophrenia prone to experiencing auditory hallucinations. Such deficits may obscure important cues for recognition of internal speech, contributing to failures of self-monitoring.

Imaging auditory hallucinations in schizophrenia

It is increasingly recognized that there are a heterogeneous range of symptoms within the syndrome of schizophrenia and that some of these also occur frequently within other psychiatric conditions. An approach similar to that in neuropsychology, where cases are grouped based on a discrete deficit, or in this case a discrete symptom, rather than a cause or diagnosis, may be useful in exploring the neural correlates of psychotic symptomatology. Functional neuroimaging provides an excellent tool for investigating the in vivo cortical function of patients with schizophrenia. Auditory verbal hallucinations are one of the most commonly occurring psychotic symptoms in schizophrenia; and this paper examines the progress that has been made in utilizing neuroimaging techniques to investigate auditory hallucinations in schizophrenia and review potential implications for treatment and future directions for research.