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Biomedical subjects

André Aleman

Publications and source records attributed to André Aleman.

At least 19 recordsLinked to original sources
PubMed2006

Associations between delusion proneness and personality structure in non-clinical participants: comparison between young and elderly samples.

BACKGROUND: Few studies have explored the prevalence of delusions in the non-clinical, elderly population. In addition, the association between personality structure and delusions remains poorly investigated. The aims of the present study were, first, to explore the relation between age and the prevalence of delusion proneness and, second, to examine the association between personality and delusion proneness in young and elderly participants. SAMPLING AND METHODS: A sample of young (n = 343; aged 18-30 years) and elderly (n = 183; aged 60-75 years) non-clinical participants completed the 21-item version of the Peters et al. Delusions Inventory (PDI-21), an elaborated and validated version of the Launay-Slade Hallucinations Scale, and the revised version of the NEO Personality Inventory (NEO-PI-R). RESULTS: Mean scores on the PDI-21 for the young and elderly participants were compared. An independent t test revealed that the total mean scores were significantly higher for young participants compared to elderly participants. PDI-21 items were then re-grouped into previously validated factors. Independent t tests revealed that young participants had significantly higher scores for items related to suspiciousness and persecutory ideas, thought disturbances and jealousy, grandiose ideas, paranormal beliefs and apocalyptic ideas. In contrast, elderly participants scored significantly higher than young participants on the religious ideation factor. Associations between scores on the NEO-PI-R and the PDI-21 were then examined for the two groups. For the young sample, correlational analyses revealed a significant relationship between the total score on the PDI-21 and scores on the openness, neuroticism and agreeability facets of the NEO-PI-R. For the elderly sample, correlational analyses revealed a significant relationship between the total score on the PDI-21 and the openness facet of the NEO-PI-R. DISCUSSION: Results from the study reveal that delusional ideation is a relatively common experience for both young and elderly non-clinical participants. In addition, findings are in line with studies suggesting that neuroticism and aspects related to neuroticism increase the risk for the development of psychotic symptoms such as delusions. However, it is important to mention that, because the present study includes non-clinical subjects and is a cross-sectional study, more research is needed.

Adolescent↗
PubMed2006

Behavioral inhibition system (BIS), behavioral activation system (BAS) and schizophrenia: relationship with psychopathology and physiology.

OBJECTIVE: The Behavioral Inhibition System (BIS) and the Behavioral Activation System (BAS) have been conceptualized as two neural motivational systems that regulate sensitivity to punishment (BIS) and reward (BAS). Imbalance in BIS and BAS levels has been reported to be related to various forms of psychopathology. Since sensitivity to stress has been supposed to be a pathway for the development of psychotic symptoms, the aim of this study is to examine BIS and BAS scores in schizophrenia and their relationship with psychopathology and physiology. METHOD: Forty-two patients with schizophrenia (26 men, 16 women), stable on atypical antipsychotics, and 37 healthy controls (17 men, 20 women) were assessed with the use of the Behavioral Inhibition and Behavioral Activation scales. Since increased average heart rate (HR) and decreased heart rate variability (HRV) have been reported in patients with schizophrenia and have been shown to correlate with inhibited behaviour, these psychophysiological measures were also obtained. The BIS/BAS data and HR/HRV data were both analyzed by a (M)ANOVA. Correlation coefficients were computed for associations between BIS/BAS data, HR/HRV data, and patient variables. RESULTS: On the BIS, patients showed higher sensitivity to threat than control subjects. Higher BIS sensitivity correlated with longer duration of illness, and lower negative symptoms on the PANSS. The BAS scores did not reveal differences between patients and controls. In patients, low BAS sensitivity correlated with low dosage of medication. On the physiological measures patients showed a significantly higher HR and lower HRV compared to controls, which was limited to clozapine treated patients. No correlations were found between HR/HRV scores and BIS/BAS scores or patient variables. CONCLUSIONS: Male as well as female patients with schizophrenia are more sensitive to threat than healthy controls. This may reflect a trait-related characteristic, and is not reflected in state-related psychophysiological measures.

Adult↗
PubMed2006

X Chromosomal effects on social cognitive processing and emotion regulation: A study with Klinefelter men (47,XXY).

Studying Klinefelter syndrome (47,XXY), a genetically defined disorder characterized by the presence of an additional X chromosome, can reveal insights into genotype-phenotype associations. Increased vulnerability to psychiatric disorders characterized by difficulties in social interactions, such as schizophrenia and autism, has been reported for this population. The reported social difficulties in 47,XXY men may arise as a consequence of impairments in the processing of social and emotional information. The present study is the first investigation of social-emotional information processing in this X chromosomal disorder. 32 Klinefelter men and 26 men from the general population, with the groups matched for age, educational level and I.Q., participated in the study. Several tasks were included, reflecting aspects of social-emotional information processing on levels of perception, experience and expression: labeling of facial expressions of emotion, emotion-cognition interactions in decision making and emotion regulation, that refers to subjective experience and identification of emotional arousal as well as verbal expression of emotions. A discrepancy between cognitive appraisal of emotions and emotional arousal was observed in Klinefelter syndrome. Taken together, Klinefelter men seem less accurate in perception of socio-emotional cues such as angry facial expressions, they are less able to identify and verbalize their emotions, but experience increased levels of emotional arousal, in comparison to the general population. Besides describing the social-emotional phenotype of this X chromosomal disorder, the present data may prove to be an important contribution to the development of more general models describing pathways to neuropsychiatric disorders characterized by social cognitive disturbances.

Adult↗
PubMed2006

Affective state and decision-making in the Ultimatum Game.

The emerging field of neuroeconomics has provided evidence that emotional as well as cognitive processes may contribute to economic decision-making. Indeed, activation of the anterior insula, a brain area involved in emotional processing, has been shown to predict decision-making in the Ultimatum Game. However, as the insula has also been implicated in other brain functions, converging evidence on the role of emotion in the Ultimatum Game is needed. In the present study, 30 healthy undergraduate students played the Ultimatum Game while their skin conductance responses were measured as an autonomic index of affective state. The results revealed that skin conductance activity was higher for unfair offers and was associated with the rejection of unfair offers in the Ultimatum Game. Interestingly, this pattern was only observed for offers proposed by human conspecifics, but not for offers generated by computers. This provides direct support for economic models that acknowledge the role of emotional brain systems in everyday decision-making.

Adult↗
PubMed2006

Insight in psychosis and neuropsychological function: meta-analysis.

BACKGROUND: One factor contributing to impaired awareness of illness (poor insight) in psychotic disorders may be neurocognitive deficits. METHOD: A systematic review and meta-analysis were conducted after data extraction. Following an overall analysis, in which measures of different cognitive domains were taken together, more fine-grained analyses investigated whether there was a specific relation with frontal executive functioning, and whether this was influenced by diagnosis or the insight scales used. RESULTS: There was a significant mean correlation between insight ratings and neurocognitive performance (mean weighted r=0.17, 95% CI 0.13-0.21, z=8.3, P<0.0001), based on 35 studies with a total of 2354 individuals. Further analyses revealed that the effect of general intellectual impairment was smaller than the specific association with executive function. This was only the case for psychosis in general, and not in an analysis limited to schizophrenia, where all cognitive domains were associated with impaired insight to a similar degree. CONCLUSIONS: Neuropsychological dysfunction, specifically impairment of set-shifting and error monitoring, contributes to poor insight in psychosis. Specific relations with different dimensions of insight and the putative role of metacognitive functions require further study.

Cognition Disorders↗
PubMed2006

Klinefelter's syndrome (karyotype 47,XXY) and schizophrenia-spectrum pathology.

Klinefelter's syndrome, characterised by a 47,XXY chromosomal pattern, has largely been associated with physical abnormalities. Here, we report high levels of schizophrenia-spectrum pathology in 32 men with this syndrome in comparison with 26 healthy controls. This may have implications for treatment of have implications for treatment of Klinefelter's syndrome and suggests that the X chromosome may be involved in the aetiology of schizophrenia.

Adult↗
PubMed2005

Strange feelings: do amygdala abnormalities dysregulate the emotional brain in schizophrenia?

Schizophrenia is widely regarded to be a neurocognitive disorder, i.e. a dysfunction of the neural and cognitive systems subserving thinking and reasoning, memory, language, attention and perception. However, although cognitive dysfunction is certainly a cardinal feature of schizophrenia, we argue that dysfunction of emotional brain systems may be even more important in understanding the disorder. Indeed, in recent years research on the emotional aspects of schizophrenia is accumulating at a high rate. Here, we review the available evidence regarding behavioral and neural manifestations of abnormal emotional systems in schizophrenia. This evidence comes from patient studies using tasks of emotion recognition, emotional expression and emotional experience. Furthermore, studies of schizophrenia patients using structural MRI have demonstrated volume reductions of the amygdala, a key structure of the emotional brain. Finally, functional fMRI studies have revealed an attenuated response of the amygdala to emotional stimuli as compared to neutral stimuli. Beyond demonstrating that dysfunction of the emotional brain is a hallmark of schizophrenia, we propose a model that integrates previous neural accounts of emotional abnormalities in schizophrenia, and specifies a neural basis for differential emotional correlates of positive and negative symptoms. Specifically, a lesion to the amygdala in combination with reduced interconnectivity with the prefrontal cortex is hypothesized to give rise to reduced emotional expression (affective flattening) and emotion recognition deficits. In contrast, an imbalance in dopamine systems may underlie increased anxiety and autonomic arousal, and the assignment of emotional salience to insignificant stimuli, associated with psychosis. We also hypothesize that the central and basolateral nuclei of the amygdala may contribute differentially to these abnormalities.

Affective Symptoms↗
PubMed2005

Repetitive transcranial magnetic stimulation over the right dorsolateral prefrontal cortex affects strategic decision-making.

Although decision-making is typically seen as a rational process, emotions play a role in tasks that include unfairness. Recently, activation in the right dorsolateral prefrontal cortex during offers experienced as unfair in the Ultimatum Game was suggested to subserve goal maintenance in this task. This is restricted to correlational evidence, however, and it remains unclear whether the dorsolateral prefrontal cortex is crucial for strategic decision-making. The present study used repetitive transcranial magnetic stimulation in order to investigate the causal role of the dorsolateral prefrontal cortex in strategic decision-making in the Ultimatum Game. The results showed that repetitive transcranial magnetic stimulation over the right dorsolateral prefrontal cortex resulted in an altered decision-making strategy compared with sham stimulation. We conclude that the dorsolateral prefrontal cortex is causally implicated in strategic decision-making in healthy human study participants.

Adult↗
PubMed2005

Feelings you can't imagine: towards a cognitive neuroscience of alexithymia.

Alexithymia, or 'no words for feelings', refers to an impairment of the ability to identify and communicate one's emotional state, in addition to diminished affect-related fantasy and imagery. A recent study by Mantani et al. reported reduced activation of the posterior cingulate cortex in people with alexithymia when they imagined a future happy event. This finding augments the emerging understanding of the neural basis of alexithymia, and potentially provides valuable insights into brain systems underlying normal emotion processing.

Affective Symptoms↗
PubMed2005

Schizophrenia and processing of facial emotions: sex matters.

The aim of this study was to examine sex differences in emotion processing in patients with schizophrenia and control subjects. To this end, 53 patients with schizophrenia (28 men and 25 women), and 42 controls (21 men and 21 women) were assessed with the use of a facial affect recognition morphing task. Accuracy and sensitivity scores were measured. Women performed better than men in labelling negative emotions. On the same task, patients performed worse than control subjects, irrespective of sex, although the largest degree of impairment was seen in male patients. In conclusion, emotion perception was disproportionally affected in men with schizophrenia relative to women. This may explain, in part, why women with schizophrenia are less impaired in social life than men suffering from this illness.

Adult↗
PubMed2005

Cognitive functioning in patients with schizophrenia and bipolar disorder: a quantitative review.

OBJECTIVE: Evidence suggests that cognitive functioning in bipolar disorder may be impaired even in euthymic states, but it is unclear if the pattern of deficits is similar to the deficits found in schizophrenia. The aim of this study was to review quantitatively the studies on cognitive performance in schizophrenia and bipolar disorder. METHODS: Articles for consideration were identified through a literature search in MEDLINE and PsycLIT in the period between 1985 and October 2004, using the keywords "schizophrenia" combined with "bipolar disorder", or "manic-depress*" or "manic" combined with "cogniti*" or "neuropsycholog*". Thirty-one studies were included that: i) evaluated cognitive performance using standardized and reliable neuropsychological testing procedures; ii) compared adult patients with schizophrenia and with bipolar disorder; iii) reported test scores of both patient groups, or exact p-values, t-values, or F-values; and iv) were published as an original article in a peer-reviewed English language journal. RESULTS: Meta-analyses of all studies indicated that patients with bipolar disorder generally perform better than patients with schizophrenia, but the distribution of effect sizes showed substantial heterogeneity. Results based on a more homogeneous subset of studies that matched patient groups on clinical and demographic characteristics pointed in the same direction, with effect sizes in the moderate range. CONCLUSIONS: Patients with bipolar disorder show better cognitive performance than patients with schizophrenia, even when matched for clinical and demographic characteristics.

Bipolar Disorder↗
PubMed2005

Childhood-onset growth hormone deficiency, cognitive function and brain N-acetylaspartate.

Cognitive deficits have been reported in adults with childhood-onset growth hormone (GH) deficiency. We evaluated cognitive deficits simultaneously with parameters for neuronal integrity using (1)H magnetic resonance spectroscopy (MRS) in a cross-sectional design. We studied 11 adults (mean age 24.5 years) with childhood-onset GH deficiency, which persisted after reaching final height. All subjects were evaluated after interruption of GH supplementation for at least 3 months. We performed neuropsychological assessment (NPA) using tests evaluating memory, mental processing speed, reading ability and executive functioning. MRS was used to assess brain N-acetylaspartate (NAA)/choline ratios. Data were compared with an age-, sex- and education-matched control group (n=9, mean age 27.3 years). NPA demonstrated attenuated performance of the patients in the delayed verbal memory recall score (P<0.05) and the trail making A test (P<0.05), a measure of planning of behavior, processing speed and attention. Other neuropsychological tests were not affected. NAA/choline ratios were significantly reduced (P<0.01) in GH deficient subjects. Specific cognitive defects indicating affected memory and attention were found in patients with childhood-onset GH deficiency. These defects occur simultaneously with reduced neuronal integrity.

Adolescent↗
PubMed2005

Vascular risk factors and cognitive function in a sample of independently living men.

Decline of cognitive function with age may be due, in part, to atherosclerotic changes. The aim of the present study was to determine the relative contribution of vascular risk factors to cognitive functioning in a non-clinical sample of men. Cognitive tests were administered to 400 independently living men aged 40-80 years. The measures included short-term memory, speed of information processing, verbal and visual long-term memory, word fluency, cognitive flexibility, an estimate of verbal intelligence, and general cognitive status. Systolic blood pressure, serum cholesterol, glucose levels, smoking, alcohol intake, body mass index, homocysteine and peak expiratory flow rate were entered as independent variables into a multiple regression model, after adjustment for age and education. Hierarchical regression analyses revealed independent contributions of the combination of vascular risk factors in explaining the observed variance in performance on tests of cognitive functioning targeted at information processing capacity and speed and general cognitive status. Of the individual predictor variables, alcohol intake and homocysteine levels were significantly associated with processing capacity and speed, and peak expiratory flow rate was significantly associated with general cognitive status. Our results indicate that the combination of several independent vascular risk factors predicts performance on cognitive tests of information processing capacity and speed in a population-based sample of middle-aged and elderly men.

Activities of Daily Living↗
PubMed2005

What is said or how it is said makes a difference: role of the right fronto-parietal operculum in emotional prosody as revealed by repetitive TMS.

Emotional signals in spoken language can be conveyed by semantic as well as prosodic cues. We investigated the role of the fronto-parietal operculum, a somatosensory area where the lips, tongue and jaw are represented, in the right hemisphere to detection of emotion in prosody vs. semantics. A total of 14 healthy volunteers participated in the present experiment, which involved transcranial magnetic stimulation (TMS) in combination with frameless stereotaxy. As predicted, compared with sham stimulation, TMS over the right fronto-parietal operculum differentially affected the reaction times for detection of emotional prosody vs. emotional semantics, showing that there is a dissociation at a neuroanatomical level. Detection of withdrawal emotions (fear and sadness) in prosody was delayed significantly by TMS. No effects of TMS were observed for approach emotions (happiness and anger). We propose that the right fronto-parietal operculum is not globally involved in emotion evaluation, but sensitive to specific forms of emotional discrimination and emotion types.

Adult↗
PubMed2005

Object versus spatial visual mental imagery in patients with schizophrenia.

OBJECTIVE: Recent research has revealed a larger impairment of object perceptual discrimination than of spatial perceptual discrimination in patients with schizophrenia. It has been suggested that mental imagery may share processing systems with perception. We investigated whether patients with schizophrenia would show greater impairment regarding object imagery than spatial imagery. METHODS: Forty-four patients with schizophrenia and 20 healthy control subjects were tested on a task of object visual mental imagery and on a task of spatial visual mental imagery. Both tasks included a condition in which no imagery was needed for adequate performance, but which was in other respects identical to the imagery condition. This allowed us to adjust for nonspecific differences in individual performance. RESULTS: The results revealed a significant difference between patients and controls on the object imagery task (F(1,63) = 11.8, p = 0.001) but not on the spatial imagery task (F(1,63) = 0.14, p = 0.71). To test for a differential effect, we conducted a 2 (patients v. controls) small ha, Cyrillic 2 (object task v. spatial task) analysis of variance. The interaction term was statistically significant (F(1,62) = 5.2, p = 0.026). CONCLUSIONS: Our findings suggest a differential dysfunction of systems mediating object and spatial visual mental imagery in schizophrenia.

Adult↗
PubMed2004

Neurobiology of emotion and high risk for schizophrenia: role of the amygdala and the X-chromosome.

Abnormalities in emotion processing and in structure of the amygdala have consistently been documented in schizophrenia. A major question is whether amygdala abnormalities reflect a genetic vulnerability for the disease. In the present paper, we reviewed Magnetic Resonance Imaging (MRI) studies that reported amygdala measures in several high-risk populations: subjects from the general population with subclinical schizophrenia symptoms and relatives of schizophrenia patients. In addition, we reviewed the evidence regarding Klinefelter syndrome (characterised by an additional X-chromosome), which has also been related to an increased risk for schizophrenia. Overall, the evidence points to structural abnormalities of the amygdala in individuals at increased risk for schizophrenia. Although the genetic basis of amygdala deficits remains unclear, abnormalities (of genes) on the X-chromosome might play a role as suggested by the evidence from individuals with sex chromosome aneuploidies. We propose that amygdala abnormalities are an endophenotype in schizophrenia and may account for subtle emotional processing deficits that have been described in these high-risk groups.

Amygdala↗
PubMed2004

Cognitive deficits in relatives of patients with schizophrenia: a meta-analysis.

BACKGROUND: Schizophrenia is characterized by a generalized cognitive impairment with pronounced deficits in the domains of verbal memory, executive functioning and attention. AIM: To investigate whether cognitive deficits found in patients with schizophrenia are also found in non-affected relatives. METHOD: A meta-analytic review of the published literature on cognitive performance between relatives of schizophrenic patients and healthy controls. RESULTS: The meta-analyses yielded nine weighted effect sizes from 37 studies comprising 1639 relatives of schizophrenia patients and 1380 control subjects. The largest differences were found on verbal memory recall (d=0.54, 95% CI=0.43-0.66) and executive functioning (d=0.51, 0.36-0.67). Attentional functioning showed smaller effect sizes (d=0.28, 0.06-0.50). These effect sizes are in the moderate range. CONCLUSION: Cognitive deficits found in patients with schizophrenia are also found in non-affected relatives. This finding is consistent with the idea that certain cognitive deficiencies in relatives are caused by familial predisposition to schizophrenia and that these deficiencies might be putative endophenotypes for schizophrenia. However, our results do not address genetic causes directly. Further work is needed to determine whether certain cognitive traits are familial and whether there is co-inheritance of these traits with schizophrenia within families.

Cognition Disorders↗