Eliciting false auditory perceptions using speech frequencies and semantic priming: a signal detection approach

Associations of Cognitive Expectancies With Auditory Hallucinations and Hallucinatory-Like Experiences in Patients With Schizophrenia

BACKGROUND

Various neurocognitive models explore perceptual distortions and hallucinations in schizophrenia and the general population. A variant of predictive coding account suggests that strong priors, like cognitive expectancy, may influence perception. This study examines if stronger cognitive expectancies result in more auditory false percepts in clinical and healthy control groups, investigates group differences, and explores the association between false percepts and hallucinations.

STUDY DESIGN

Patients diagnosed with schizophrenia with current auditory hallucinations (n = 51) and without hallucinations (n = 66) and healthy controls (n = 51) underwent the False Perception Task under various expectancy conditions. All groups were examined for the presence and severity of hallucinations or hallucinatory-like experiences.

STUDY RESULTS

We observed a main effect of condition across all groups, ie, the stronger the cognitive expectancy, the greater the ratio of auditory false percepts. However, there was no group effect for the ratio of auditory false percepts. Despite modest pairwise correlations in the hallucinating group, the ratio of auditory false percepts was not predicted by levels of hallucinations and hallucinatory-like experiences in a linear mixed model.

CONCLUSIONS

The current study demonstrates that strong priors in the form of cognitive expectancies affect perception and play a role in perceptual disturbances. There is also a tentative possibility that overreliance on strong priors may be associated with hallucinations in currently hallucinating subjects. Possible, avoidable confounding factors are discussed in detail.

Cognitive correlates of auditory hallucinations in schizophrenia spectrum disorders

Auditory hallucinations (AHs) are one of the central symptoms of schizophrenia spectrum disorders (SSD). Current cognitive models of AH implicate source monitoring, top-down processes, and inhibitory control. However, research combining these processes is limited. Our study aimed to examine how source monitoring bias, top-down processes, and inhibitory control contribute to AHs in individuals with SSD. Eighty seven patients (aged 18-45 years) with SSD were included in the analyses. Participants completed cognitive tasks assessing source monitoring (Action Memory Task), top-down processes (False Perception Task; FPT), and inhibitory control (Auditory Go/NoGo task). AH was positively associated with response bias on the FPT. Correlations between AH and the other cognitive tasks were nonsignificant. Source monitoring errors correlated positively with response bias measures and negatively with Hits on the FPT. PANSS total score was positively correlated with source monitoring bias and False Alarms on the Go/NoGo task. The severity of disorganized symptoms was related to Source Monitoring Errors and False Alarms in the Go/NoGo task. Negative symptoms were associated with Hits and False Alarms in the Go/NoGo task. Future studies are necessary to further elucidate the relationships between different cognitive processes that may be related to clinical symptoms of psychosis.

Neurocognitive bases of self-monitoring of inner speech in hallucination prone individuals

Verbal hallucinations in schizophrenia patients might be seen as internal verbal productions mistaken for perceptions as a result of over-salient inner speech and/or defective self-monitoring processes. Similar cognitive mechanisms might underpin verbal hallucination proneness in the general population. We investigated, in a non-clinical sample, the cerebral activity associated with verbal hallucinatory predisposition during false recognition of familiar words -assumed to stem from poor monitoring of inner speech-vs. uncommon words. Thirty-seven healthy participants underwent a verbal recognition task. High- and low-frequency words were presented outside the scanner. In the scanner, the participants were then required to recognize the target words among equivalent distractors. Results showed that verbal hallucination proneness was associated with higher rates of false recognition of high-frequency words. It was further associated with activation of language and decisional brain areas during false recognitions of low-, but not high-, frequency words, and with activation of a recollective brain area during correct recognitions of low-, but not high-, frequency words. The increased tendency to report familiar words as targets, along with a lack of activation of the language, recollective, and decisional brain areas necessary for their judgement, suggests failure in the self-monitoring of inner speech in verbal hallucination-prone individuals.

Phantom phone signals and other hallucinatory-like experiences: Investigation of similarities and differences

Phantom Phone Signals (PPS) and other hallucinatory-like experiences (HLEs) are perceptual anomalies that are commonly reported in the general population. Both phenomena concern the same sensory modality, but PPS are restricted to smartphone use. The current study aimed to assess similarities and differences between these types of anomalies in relation to general psychopathology, metacognitive beliefs about perception, smartphone dependence, and susceptibility to top-down influences on perception. We analyzed data from a Polish community sample (N = 236, aged 18-69). We used questions pertaining to PPS, a questionnaire pertaining to HLEs (Multi-Modality Unusual Sensory Experiences Questionnaire), and other variables of interest (Symptom Checklist-27-plus, Mobile Phone Problematic Use Scale, and the Beliefs about Perception Questionnaire). Additionally, a false-perception task manipulating cognitive expectancy (i.e., a visual cue associated with auditory stimuli vs. no visual cue) was devised to measure top-down influences on perception. Regression analyses showed that only top-down beliefs about perception predicted both PPS and HLEs. Smartphone dependency proved to be a stronger predictor of PPS than other measured variables, whereas for HLEs, general psychopathology was the strongest predictor. Current results suggest that despite sharing some mechanisms, PPS and HLEs may have independent underlying factors.

Mimicking effects of auditory verbal hallucinations on language production at the level of words, sentences and stories

Schizophrenia is characterised foremost by hallucinations, delusions and disorganised speech. Deficits in the internal speech monitor may contribute to the development of auditory-verbal hallucinations. This study investigates potential effects in the opposite direction: could the presence of auditory-verbal hallucinations have an effect on speech production? To this end, a recent mimicking/simulation approach was adopted for 40 healthy participants who perceived either white noise or hallucination-like speech recordings during different language production tasks with increasing demands: picture naming, verbal fluency with and without category switch, sentence production, and discourse. In line with reports about real schizophrenia cases in the literature, mimicking auditory-verbal hallucinations affected verbal fluency (switch condition) and sentence production (duration) in a different way than mere noise. These effects were not correlated, suggesting that hallucinations may even affect different levels of linguistic complexity in different ways. Anyway, in both cases (mimicked), auditory hallucination appear to contribute to the emergence of disordered speech. The mimicking/simulation paradigm may in future help to identify and disentangle the various factors contributing to disorganised speech in schizophrenia. They may also support the development and implementation of new protocols, e.g., in speech and language therapy in persons with schizophrenia in order to improve their communication skills despite the presence of auditory-verbal hallucinations.