Frank Laroi

The hallucinating brain : A review of structural and functional neuroimaging studies of hallucinations

Hallucinations remains one of the most intriguing phenomena in psychopathology. In the past two decades the advent of neuroimaging techniques have allowed researchers to investigate what is happening in the brain of those who experience hallucinations. In this article we review both structural and functional neuroimaging studies of patients with auditory and visual hallucinations as well as a small number of studies that have assessed cognitive processes associated with hallucinations in healthy volunteers. The current literature suggests that in addition to secondary (and occasionally primary) sensory cortices, dysfunction in prefrontal premotor, cingulate, subcortical and cerebellar regions also seem to contribute to hallucinatory experiences. Based on the findings of these studies we tentatively propose a neurocognitive model in which both bottom-up and top-down processes interact to produce these erroneous percepts. Finally, directions for future work are discussed.

Auditory Hallucinations in Schizophrenia and Nonschizophrenia Populations: A Review and Integrated Model of Cognitive Mechanisms

While the majority of cognitive studies on auditory hallucinations (AHs) have been conducted in schizophrenia (SZ), an increasing number of researchers are turning their attention to different clinical and nonclinical populations, often using SZ findings as a model for research. Recent advances derived from SZ studies can therefore be utilized to make substantial progress on AH research in other groups. The objectives of this article were to (1) present an up-to-date review regarding the cognitive mechanisms of AHs in SZ, (2) review findings from cognitive research conducted in other clinical and nonclinical groups, and (3) integrate these recent findings into a cohesive framework. First, SZ studies show that the cognitive underpinnings of AHs include self-source-monitoring deficits and executive and inhibitory control dysfunctions as well as distortions in top-down mechanisms, perceptual and linguistic processes, and emotional factors. Second, consistent with SZ studies, findings in other population groups point to the role of top-down processing, abnormalities in executive inhibition, and negative emotions. Finally, we put forward an integrated model of AHs that incorporates the above findings. We suggest that AHs arise from an interaction between abnormal neural activation patterns that produce salient auditory signals and top-down mechanisms that include signal detection errors, executive and inhibition deficits, a tapestry of expectations and memories, and state characteristics that influence how these experiences are interpreted. Emotional factors play a particular prominent role at all levels of this hierarchy. Our model is distinctively powerful in explaining a range of phenomenological characteristics of AH across a spectrum of disorders.

Emotional processing in a non-clinical psychosis-prone sample

Symptoms of psychosis have been proposed to form part of a continuous distribution of experiences in the general population rather than being an all-or-nothing phenomenon. Indeed, schizotypal signs have been reported in subjects from non-clinical samples. Emotional processing has been documented to be deficient in schizophrenia. In the present study, we tested the hypothesis whether putatively psychosis-prone subjects would show abnormalities in emotion processing. Based on the extremes of Launay-Slade Hallucination Scale (LSHS) ratings of 200 undergraduate students, two groups of subjects (total N=40) were selected. All 40 participants filled in the Schizotypal Personality Questionnaire (SPQ). We compared both groups on an alexithymia questionnaire and on four behavioral emotional information processing tasks. Hallucination-proneness was associated with an increased subjective emotional arousal and fantasy-proneness. Although no differences between the high and low group were observed on three behavioral emotion processing tasks, on the affective word-priming task presentation of emotional stimuli was associated with longer reactions times to neutral words in high schizotypal subjects. Also, SPQ scores correlated with several emotion processing tasks. We conclude that these findings lend partial support to the hypothesis of continuity between symptoms characteristic of schizophrenia and psychosis-related phenomena in the normal population.

The characteristic features of auditory verbal hallucinations in clinical and nonclinical groups: state-of-the-art overview and future directions.

Despite a growing interest in auditory verbal hallucinations (AVHs) in different clinical and nonclinical groups, the phenomenological characteristics of such experiences have not yet been reviewed and contrasted, limiting our understanding of these phenomena on multiple empirical, theoretical, and clinical levels. We look at some of the most prominent descriptive features of AVHs in schizophrenia (SZ). These are then examined in clinical conditions including substance abuse, Parkinsons disease, epilepsy, dementia, late-onset SZ, mood disorders, borderline personality disorder, hearing impairment, and dissociative disorders. The phenomenological changes linked to AVHs in prepsychotic stages are also outlined, together with a review of AVHs in healthy persons. A discussion of key issues and future research directions concludes the review.

A French Adaptation of the UPPS Impulsive Behavior Scale

Impulsivity is an important and multifaceted psychological construct. Recently, Whiteside and Lynam (2001) have developed the UPPS Impulsive Behavior Scale that distinguishes four dimensions of impulsivity: Urgency, lack of Premeditation, lack of Perseverance, and Sensation seeking. In the present study, we investigated the psychometric properties of a French adaptation of the UPPS Impulsive Behavior Scale. Two hundred and thirty-four undergraduate students completed the UPPS Scale. Exploratory and confirmatory analyses revealed a four factors solution similar to that found in the original study. Also, the results indicated that there was good to very good internal reliability for the four subscales.

Auditory verbal hallucinations in persons with and without a need for care

Auditory verbal hallucinations (AVH) are complex experiences that occur in the context of various clinical disorders. AVH also occur in individuals from the general population who have no identifiable psychiatric or neurological diagnoses. This article reviews research on AVH in nonclinical individuals and provides a cross-disciplinary view of the clinical relevance of these experiences in defining the risk of mental illness and need for care. Prevalence rates of AVH vary according to measurement tool and indicate a continuum of experience in the general population. Cross-sectional comparisons of individuals with AVH with and without need for care reveal similarities in phenomenology and some underlying mechanisms but also highlight key differences in emotional valence of AVH, appraisals, and behavioral response. Longitudinal studies suggest that AVH are an antecedent of clinical disorders when combined with negative emotional states, specific cognitive difficulties and poor coping, plus family history of psychosis, and environmental exposures such as childhood adversity. However, their predictive value for specific psychiatric disorders is not entirely clear. The theoretical and clinical implications of the reviewed findings are discussed, together with directions for future research.

Further evidence of the multi-dimensionality of hallucinatory predisposition: factor structure of a modified version of the Launay-Slade Hallucinations Scale in a normal sample

Recent years has seen an increasing interest in the hallucinatory experience, including investigations of its phenomenological prevalence and character both in pathological and normal (predisposed) populations. We investigated the multi-dimensionality of hallucinatory experiences in 265 subjects from the normal population, who completed a modified version of the Launay-Slade Hallucinations Scale. Principal components analysis was performed on the data. Four factors were obtained loading on items reflecting (1) sleep-related hallucinatory experiences (2) vivid daydreams (3) intrusive thoughts or realness of thought and (4) auditory hallucinations. The results offer further evidence of the multi-dimensionality of hallucinatory disposition in the normal population. Directions for future research in hallucinatory predisposition are discussed.

The effects of emotional salience, cognitive effort and meta-cognitive beliefs on a reality monitoring task in hallucination-prone subjects

OBJECTIVES A tendency to externalize internal information on reality monitoring tasks has been documented in psychiatric patients with hallucinations. Furthermore, previous studies suggest that factors such as the emotional salience of the material, cognitive effort and meta-cognitive beliefs are important contributory factors in this tendency to externalize internal information on reality monitoring tasks. However, few studies have investigated these aspects in hallucination-prone subjects. Also, these factors have never been examined simultaneously. In the following study we wished to examine the effects of emotional salience, cognitive effort and meta-cognitive beliefs on reality monitoring functioning in hallucination-prone subjects. DESIGN Between-participants group design. METHOD One hundred normal subjects were administered a reality monitoring task. Words were presented by the experimenter. After each word, subjects were asked to say the first word that came to their mind. Words varied in terms of emotional valence and cognitive effort (high cognitive effort for words requiring longer latency times to associate a word and vice versa). Following a delay, words were presented consisting of those already presented by the experimenter or the subject (old) and those never presented before (new). For each word, subjects were required to identify whether the word was old or new. If the word was identified as old, subjects were required to identify the source of the word (subject or experimenter). Subjects also completed a questionnaire assessing meta-cognitive beliefs. RESULTS Subjects were grouped according to their scores on a revised and elaborated version of the Launay-Slade Hallucinations Scale (LSHS). Those with scores within the top 25% were included in the hallucination-prone group (HP) (N = 25), whereas scores within the lower 25% were included in the non-hallucination-prone group (NHP) (N = 25). Results showed that the HP subjects had significantly more source discrimination errors than NHP subjects for self-generated items. In other words, HP subjects tended to misattribute to the experimenter items that they had produced themselves. This pattern was especially marked with emotionally charged material and with words that required more cognitive effort. In addition, HP subjects scored significantly higher on a scale assessing meta-cognitive beliefs compared with NHP subjects. Finally, scores on a scale assessing meta-cognitive beliefs were positively associated with source discrimination errors. CONCLUSIONS These results suggest that cognitive effort, emotional salience and meta-cognitive beliefs all play a prominent role in the externalizing bias in hallucination-prone subjects. The results also provide evidence for the validity of the idea of a continuity between hallucination-prone subjects and psychotic patients with hallucinations on reality monitoring tasks, including a number of contributing factors in the occurrence of hallucinations.

Mindful Attention Awareness Scale (MAAS) : psychometric properties of the French translation and exploration of its relations with emotion regulation strategies

Over the past few years, several questionnaires have been developed to measure mindfulness. The Mindful Attention Awareness Scale (MAAS) was created to specifically capture attention and awareness in daily life (Brown & Ryan, 2003). In this article, we present a French adaptation of the MAAS. In the 1st study, we explored the psychometric properties of this adaptation. In the 2nd study, we investigated its relation to cognitive emotion regulation and depressive symptomatology using path analysis. As in the original version of the MAAS, the French adaptation has a strong 1-factor structure. Moreover, there was a negative relationship between the MAAS and the severity of depressive symptoms, both directly and indirectly. The indirect pathway was mediated by the nonadaptive cognitive emotion regulation strategy of self-blame and the adaptive cognitive emotion regulation strategy of positive reappraisal. In conclusion, this questionnaire represents a valid mindfulness measure for French-speaking clinicians and researchers.

Visual Hallucinations in the Psychosis Spectrum and Comparative Information From Neurodegenerative Disorders and Eye Disease

Much of the research on visual hallucinations (VHs) has been conducted in the context of eye disease and neurodegenerative conditions, but little is known about these phenomena in psychiatric and nonclinical populations. The purpose of this article is to bring together current knowledge regarding VHs in the psychosis phenotype and contrast this data with the literature drawn from neurodegenerative disorders and eye disease. The evidence challenges the traditional views that VHs are atypical or uncommon in psychosis. The weighted mean for VHs is 27% in schizophrenia, 15% in affective psychosis, and 7.3% in the general community. VHs are linked to a more severe psychopathological profile and less favorable outcome in psychosis and neurodegenerative conditions. VHs typically co-occur with auditory hallucinations, suggesting a common etiological cause. VHs in psychosis are also remarkably complex, negative in content, and are interpreted to have personal relevance. The cognitive mechanisms of VHs in psychosis have rarely been investigated, but existing studies point to source-monitoring deficits and distortions in top-down mechanisms, although evidence for visual processing deficits, which feature strongly in the organic literature, is lacking. Brain imaging studies point to the activation of visual cortex during hallucinations on a background of structural and connectivity changes within wider brain networks. The relationship between VHs in psychosis, eye disease, and neurodegeneration remains unclear, although the pattern of similarities and differences described in this review suggests that comparative studies may have potentially important clinical and theoretical implications.