Sensory contributions to impaired prosodic processing in schizophrenia

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.

Deficits in implicit attention to social signals in schizophrenia and high risk groups: behavioural evidence from a new illusion

Background

An increasing body of evidence suggests that the apparent social impairments observed in schizophrenia may arise from deficits in social cognitive processing capacities. The ability to process basic social cues, such as gaze direction and biological motion, effortlessly and implicitly is thought to be a prerequisite for establishing successful social interactions and for construing a sense of “social intuition.” However, studies that address the ability to effortlessly process basic social cues in schizophrenia are lacking. Because social cognitive processing deficits may be part of the genetic vulnerability for schizophrenia, we also investigated two groups that have been shown to be at increased risk of developing schizophrenia-spectrum pathology: first-degree relatives of schizophrenia patients and men with Klinefelter syndrome (47,XXY).

Results

We compared 28 patients with schizophrenia, 29 siblings of patients with schizophrenia, and 29 individuals with Klinefelter syndrome with 46 matched healthy control subjects on a new paradigm. This paradigm measures one's susceptibility for a bias in distance estimation between two agents that is induced by the implicit processing of gaze direction and biological motion conveyed by these agents. Compared to control subjects, patients with schizophrenia, as well as siblings of patients and Klinefelter men, showed a lack of influence of social cues on their distance judgments.

Conclusions

We suggest that the insensitivity for social cues is a cognitive aspect of schizophrenia that may be seen as an endophenotype as it appears to be present both in relatives who are at increased genetic risk and in a genetic disorder at risk for schizophrenia-spectrum psychopathology. These social cue–processing deficits could contribute, in part, to the difficulties in higher order social cognitive tasks and, hence, to decreased social competence that has been observed in these groups.

Altered lateralisation of emotional prosody processing in schizophrenia

Alterations of cerebral lateralisation in schizophrenia have been reported consistently, and a reduced left-lateralisation has been suggested for language functions. Speech contains non-verbal information, e.g. prosody, and on a behavioural level, the extraction of emotional information from prosody is often impaired in schizophrenia. A previous functional magnetic resonance imaging study suggests increased left-lateralisation in schizophrenia during prosody processing, but did not disentangle effects of speech processing as such and emotional prosody processing. Here, we used meaningless syllables spoken with neutral, angry or fearful speech melody and measured blood oxygen level-dependent (BOLD) responses in 15 in-patients with schizophrenia and 15 healthy control participants matched for age and gender. Lateralisation indices were calculated for responses to emotional versus neutral prosody, and for all types of prosody versus baseline. Compared to control participants, patients with schizophrenia showed an increased right-lateralisation of emotional and non-emotional prosody processing in the temporal and parietal cortex. This right-lateralisation was increased in patients with reduced right-handedness and decreased in patients with stronger negative symptoms, particularly affective blunting, and with longer hospitalisation. Although patients with schizophrenia performed worse in emotion identification, this deficit was not related to lateralisation indices. Enhanced right-lateralisation to prosody resembles previous findings on laterality changes in speech processing and might suggest a common underlying cause in the organization of language functions.

Schizophrenia from a neural circuitry perspective: advancing toward rational pharmacological therapies

Schizophrenia is a severe disorder that disrupts the function of multiple brain systems, resulting in impaired social and occupational functioning. The etiology and pathogenesis of schizophrenia appear to involve the interplay of a potentially large number of genetic liabilities and adverse environmental events that disrupt brain developmental pathways. In this Review, we discuss a strategy for determining how particular common and core clinical features of the illness are associated with pathophysiology in certain circuits of the cerebral cortex. The identification of molecular alterations in these circuits is providing critical insights for the rational development of new therapeutic interventions.

Facial emotion perception in schizophrenia: a meta-analytic review

OBJECTIVES

A considerable body of literature has reported on emotion perception deficits and the relevance to clinical symptoms and social functioning in schizophrenia. Studies published between 1970-2007 were examined regarding emotion perception abilities between patient and control groups and potential methodological, demographic, and clinical moderators. DATA SOURCES AND REVIEW: Eighty-six studies were identified through a computerized literature search of the MEDLINE, PsychINFO, and PubMed databases. A quality of reporting of meta-analysis standard was followed in the extraction of relevant studies and data. Data on emotion perception, methodology, demographic and clinical characteristics, and antipsychotic medication status were compiled and analyzed using Comprehensive Meta-analysis Version 2.0 (Borenstein M, Hedges L, Higgins J and Rothstein H. Comprehensive Meta-analysis. 2. Englewood, NJ: Biostat; 2005).

RESULTS

The meta-analysis revealed a large deficit in emotion perception in schizophrenia, irrespective of task type, and several factors that moderated the observed impairment. Illness-related factors included current hospitalization and--in part--clinical symptoms and antipsychotic treatment. Demographic factors included patient age and gender in controls but not race.

CONCLUSION

Emotion perception impairment in schizophrenia represents a robust finding in schizophrenia that appears to be moderated by certain clinical and demographic factors. Future directions for research on emotion perception are discussed.

Validation of affective and neutral sentence content for prosodic testing

Conducting a study of emotional prosody often requires that one have a valid set of stimuli for assessing perceived emotion in vocal intonation. In this study, we created a list of sentences with both affective and neutral content, and then validated them against rater opinion. Participants read sentences with content that implied happiness, sadness, anger, fear, or neutrality and rated how well they could imagine each sentence being expressed in each emotion. Coefficients of variation and intraclass correlations were calculated to narrow the list to affective sentences that had high agreement and neutral sentences that had low agreement. We found that raters could easily identify most emotional content and did not ascribe any unique emotion to most neutral content. We also found differences between the intensity of male and female ratings. The final list of sentences is available on the Internet (www.med.upenn.edu/bbl/) and can be recorded for use as stimuli for prosodic studies.

Reduced dendritic spine density in auditory cortex of subjects with schizophrenia

We have previously identified reductions in mean pyramidal cell somal volume in deep layer 3 of BA 41 and 42 and reduced axon terminal density in deep layer 3 of BA 41. In other brain regions demonstrating similar deficits, reduced dendritic spine density has also been identified, leading us to hypothesize that dendritic spine density would also be reduced in BA 41 and 42. Because dendritic spines and their excitatory inputs are regulated in tandem, we further hypothesized that spine density would be correlated with axon terminal density. We used stereologic methods to quantify a marker of dendritic spines, spinophilin-immunoreactive (SP-IR) puncta, in deep layer 3 of BA 41 and 42 of 15 subjects with schizophrenia, each matched to a normal comparison subject. The effect of long-term haloperidol exposure on SP-IR puncta density was evaluated in nonhuman primates. SP-IR puncta density was significantly lower by 27.2% in deep layer 3 of BA 41 in the schizophrenia subjects, and by 22.2% in deep layer 3 of BA 42. In both BA 41 and 42, SP-IR puncta density was correlated with a marker of axon terminal density, but not with pyramidal cell somal volume. SP-IR puncta density did not differ between haloperidol-exposed and control monkeys. Lower SP-IR puncta density in deep layer 3 of BA 41 and 42 of subjects with schizophrenia may reflect concurrent reductions in excitatory afferent input. This may contribute to impairments in auditory sensory processing that are present in subjects with schizophrenia.

Auditory processing abnormalities in schizotypal personality disorder: an fMRI experiment using tones of deviant pitch and duration

BACKGROUND

One of the cardinal features of schizotypal personality disorder (SPD) is language abnormalities. The focus of this study was to determine whether or not there are also processing abnormalities of pure tones differing in pitch and duration in SPD.

METHODS

Thirteen neuroleptic-naïve male subjects met full criteria for SPD and were group-matched on age and parental socio-economic status to 13 comparison subjects. Verbal learning was measured with the California Verbal Learning Test. Heschl's gyrus volumes were measured using structural MRI. Whole-brain fMRI activation patterns in an auditory task of listening to tones including pitch and duration deviants were compared between SPD and control subjects. In a second and separate ROI analysis we found that peak activation in superior temporal gyrus (STG), Brodmann Areas 41 and 42, was correlated with verbal learning and clinical measures derived from the SCID-II interview.

RESULTS

In the region of the STG, SPD subjects demonstrated more activation to pitch deviants bilaterally (p<0.001); and to duration deviants in the left hemisphere (p=0.005) (two-sample t). SPD subjects also showed more bilateral parietal cortex activation to duration deviants. In no region did comparison subjects activate more than SPD subjects in either experiment. Exploratory correlations for SPD subjects suggest a relationship between peak activation on the right for deviant tones in the pitch experiment with odd speech and impaired verbal learning. There was no difference between groups on Heschl's gyrus volume.

CONCLUSIONS

These data suggest that SPD subjects have inefficient or hyper-responsive processing of pure tones both in terms of pitch and duration deviance that is not attributable to smaller Heschl's gyrus volumes. Finally, these auditory processing abnormalities may have significance for the odd speech heard in some SPD subjects and downstream language and verbal learning deficits.

The processing of emotional prosody and semantics in schizophrenia: relationship to gender and IQ

BACKGROUND

Female patients with schizophrenia are less impaired in social life than male patients. Because social impairment in schizophrenia has been found to be associated with deficits in emotion recognition, we examined whether the female advantage in processing emotional prosody and semantics is preserved in schizophrenia.

METHOD

Forty-eight patients (25 males, 23 females) and 46 controls (23 males, 23 females) were assessed using an emotional language task (in which healthy women generally outperform healthy men), consisting of 96 sentences in four conditions: (1) neutral-content/emotional-tone (happy, sad, angry or anxious); (2) neutral-tone/emotional-content; (3) emotional-tone/incongruous emotional-content; and (4) emotional-content/incongruous emotional-tone. Participants had to ignore the emotional-content in the third condition and the emotional-tone in the fourth condition. In addition, participants were assessed with a visuospatial task (in which healthy men typically excel). Correlation coefficients were computed for associations between emotional language data, visuospatial data, IQ measures and patient variables.

RESULTS

Overall, on the emotional language task, patients made more errors than control subjects, and women outperformed men across diagnostic groups. Controlling for IQ revealed a significant effect on task performance in all groups, especially in the incongruent tasks. On the rotation task, healthy men outperformed healthy women, but male patients, female patients and female controls obtained similar scores.

CONCLUSION

The advantage in emotional prosodic and semantic processing in healthy women is preserved in schizophrenia, whereas the male advantage in visuospatial processing is lost. These findings may explain, in part, why social functioning is less compromised in women with schizophrenia than in men.

Impaired multisensory processing in schizophrenia: deficits in the visual enhancement of speech comprehension under noisy environmental conditions

BACKGROUND

Viewing a speaker's articulatory movements substantially improves a listener's ability to understand spoken words, especially under noisy environmental conditions. In this study we investigated the ability of patients with schizophrenia to integrate visual and auditory speech. Our objective was to determine to what extent they experience benefit from visual articulation and to detail under what listening conditions they might show the greatest impairments.

METHODS

We assessed the ability to recognize auditory and audiovisual speech in different levels of noise in 18 patients with schizophrenia and compared their performance with that of 18 healthy volunteers. We used a large set of monosyllabic words as our stimuli in order to more closely approximate performance in everyday situations.

RESULTS

Patients with schizophrenia showed deficits in their ability to derive benefit from visual articulatory motion. This impairment was most pronounced at signal-to-noise levels where multisensory gain is known to be maximal in healthy control subjects. A surprising finding was that despite known early auditory sensory processing deficits and reports of impairments in speech processing in schizophrenia, patients' performance in unisensory auditory speech perception remained fully intact.

CONCLUSIONS

Thus, the results showed a specific deficit in multisensory speech processing in the absence of any measurable deficit in unisensory speech processing and suggest that sensory integration dysfunction may be an important and, to date, rather overlooked aspect of schizophrenia.

Impaired perception of negative emotional prosody in schizophrenia

This paper aims to report on the perception of emotional prosody in schizophrenia and to discuss its relationship with performance on neurocognitive measures. It consists of a comparison of 20 clinically stable schizophrenia patients with 20 healthy controls. Schizophrenia patients were impaired in emotional prosody perception, in particular in the perception of negative emotions. This impairment could not be explained on the basis of task difficulty or a general impairment in the decoding of speech intonation. Emotional prosody perception correlated moderately strongly with neurocognitive measures. We did not find a negative bias in the perception of emotional prosody.

The effects of familiarity and emotional expression on face processing examined by ERPs in patients with schizophrenia

BACKGROUND

The main objective of the study was to determine whether patients with schizophrenia are deficient relative to controls in the processing of faces at different levels of familiarity and types of emotion and the stage where such differences may occur.

METHODS

ERPs based on 18 patients with schizophrenia and 18 controls were compared in a face identification task at three levels of familiarity (unknown, familiar, subject's own) and for three types of emotion (disgust, smiling, neutral).

RESULTS

The schizophrenic group was less accurate than controls in the face processing, especially for unknown faces and those expressing negative emotions such as disgust. P1 and N170 amplitudes were lower and P1, N170, P250 amplitudes were of slower onset in patients with schizophrenia. N170 and P250 amplitudes were modulated by familiarity and face expression in a different manner in patients than controls.

CONCLUSIONS

Schizophrenia is associated with a genelarized defect of face processing, both in terms of familiarity and emotional expression, attributable to deficient processing at sensory (P1) and perceptual (N170) stages. These patients appear to have difficulty in encoding the structure of a face and thereby do not evaluate correctly familiarity and emotion.

Anatomical evidence of impaired feedforward auditory processing in schizophrenia

BACKGROUND

Somal volumes of pyramidal cells are reduced within feedforward but not feedback circuits in areas 41 and 42 of the auditory cortex of subjects with schizophrenia. Because neuronal somal volume depends on both the number of axonal terminations onto and furnished by the neuron, we hypothesized that axon terminal densities are reduced in feedforward but not feedback auditory pathways in subjects with schizophrenia.

METHODS

We used stereologic methods to quantify the density of a marker of axon terminals, synaptophysin-immunoreactive (SY-IR) puncta, in areas 41 and 42 of 15 subjects with schizophrenia and matched normal comparison subjects. The effect of long-term haloperidol exposure on density of SY-IR puncta was similarly evaluated in nonhuman primates.

RESULTS

Synaptophysin-immunoreactive puncta density was 13.6% lower in deep layer 3 of area 41 in the schizophrenia subjects but was not changed in layer 1 of area 41 or in deep layer 3 of area 42. Density of SY-IR puncta did not differ between haloperidol-exposed and control monkeys.

CONCLUSIONS

Reduction of SY-IR puncta density is selective for feedforward circuits within primary auditory cortex of subjects with schizophrenia. This deficit may contribute to impairments in auditory sensory processing in this disorder.

A review of emotion deficits in schizophrenia

Emotion deficits in schizophrenia have been described since the time of Kraepelin. However, no comprehensive review of clinical emotion studies has ever been conducted, in this work, studies that used diagnostic criteria and were published in English were selected from an extensive PubMed search. Fifty-five studies on emotion expression repeatedly showed that individuals with schizophrenia (IWSs) display fewer overt expressions than non patient comparison subjects (NCSs) in verbal, facial, and acoustic channels. No clear differences were found between IWSs and depressed subjects. Sixty-nine studies examined emotion experience in schizophrenia. IWSs report higher anhedonia, and they tend to show more negative emotions in real-life event studies. In evocative studies, they report a similar degree of pleasantness and a similar or higher degree of unpleasantness. From 110 studies, ii can be concluded that emotion recognition is impaired in schizophrenia in all channels. These deficits in social perception are correlated with neurocognitive deficits and some social skills. IWSs show dysfunction in the three domains of emotion expression, emotion experience, and emotion recognition, and these dysfunctions appear to be independent of each other across domains. These deficits in basic emotion processing may be linked to psychopathology and functional outcomes.

Neurocognitive and symptom correlates of daily problem-solving skills in schizophrenia

Functional outcome for individuals with schizophrenia has been associated with cognitive impairment. Deficits in attention, memory, speed of information processing and problem-solving skills affect independent functioning, vocational performance, and interpersonal functioning. This study investigated the relationship between neurocognitive functioning, clinical symptoms and daily problem-solving skills in seriously and persistently ill persons. Thirty-eight inpatients and outpatients were administered a neurocognitive battery for attention, working memory, processing speed, perceptual organization, and executive functioning; and semi-structured clinical interviews using the BPRS and SANS. Estimates of daily problem-solving skills were obtained using the relevant factor subscale from the Independent Living Scales (ILS-PB). Daily problem-solving skills were significantly correlated with negative symptoms, processing speed, verbal memory, and working memory scores. A regression model using an enter method suggests that working memory and negative symptoms are significant predictors of daily problem-solving skills and account for 73.2% of the variance. Further analyses demonstrate that daily problem-solving skills and negative symptoms were significantly different for inpatients and outpatients and significantly correlated with community status. The findings suggest the ILS-PB has utility as a proxy measure for assessing real-world functioning in schizophrenia.