Evelyne Rechsteiner | PubMed Health

PubMed2006

Regional gray matter volume abnormalities in the at risk mental state.

BACKGROUND: Individuals with an At Risk Mental State (ARMS) have a very high risk of developing a psychotic disorder but the basis of this risk is unclear. We addressed this issue by studying gray matter volume in this group with magnetic resonance imaging (MRI). METHODS: Thirty-five individuals with an ARMS, 25 patients with first episode schizophrenia, and 22 healthy volunteers were studied using a 1.5T MRI scanner. Twelve (34%) of the ARMS group developed schizophrenia in the 2 years subsequent to scanning. RESULTS: There were significant volumetric differences between the three groups in the left insula, superior temporal gyrus, cingulate gyrus and precuneus. In these regions, the volume in the ARMS group was smaller than in volunteers but not significantly different from that in the first episode (FE) group. Direct comparison of the ARMS and control groups revealed additional areas of reduced volume in the left medial temporal cortex. Within the ARMS group, those subjects who later developed psychosis had less gray matter than subjects who did not in the right insula, inferior frontal and superior temporal gyrus. CONCLUSIONS: The ARMS was associated with reductions in gray matter volume in areas that are also reduced in schizophrenia, suggesting that these are a correlate of an increased vulnerability to psychosis. Volumetric differences within the ARMS group may be related to the subsequent onset of schizophrenia in a subset of those at high risk.

Adolescent↗

PubMed2005

Information-processing deficits and cognitive dysfunction in panic disorder.

OBJECTIVE: The plasticity of the startle reflex, including prepulse inhibition (PPI) and habituation, provides operational measures of information processing that are abnormal in several neuropsychiatric disorders characterized by deficits in suppression or inhibition of intrusive or irrelevant stimuli. Clinically, patients with panic disorder (PD) have been described as having difficulties in the inhibition of their response to sensory and cognitive events. Because such difficulties may be the result of failures in early stages of information processing, we hypothesized that startle reactivity, PPI and habituation are deficient in unmedicated patients with PD. Moreover, we tested whether there was a relation between startle reflex measures and dysfunctional cognition. METHODS: Fourteen unmedicated patients with PD (7 men, 7 women) and 28 healthy comparison subjects (14 men, 14 women) were recruited. Acoustic startle reactivity, habituation and PPI (30-ms, 60-ms, 120-ms, 240-ms and 2000-ms interstimulus intervals) were assessed in the patients with PD and the age-matched and sex-matched healthy controls. These data for unmedicated patients with PD were compared with those for 24 medicated patients with PD. Moreover, dysfunctional cognition in patients with PD was measured using the Body Sensations Questionnaire. RESULTS: Unmedicated patients with PD exhibited increased startle reactivity, reduced habituation and significantly reduced PPI in the 30-ms, 60-ms, 120-ms and 240-ms prepulse conditions. Furthermore, in unmedicated patients with PD, increased startle response and decreased habituation were correlated significantly with higher cognitive dysfunction scores, but this was not the case for PPI. CONCLUSIONS: These data indicate that the early stages of sensory information processing are abnormal in patients with PD in the absence of medication. The observed deficits in PPI and habituation could reflect a more generalized difficulty in suppressing or gating information in PD. The correlation between cognitive symptoms and higher startle response and deficient habituation supports the hypothesis that subjects with PD have abnormalities in the early stages of information processing that lead to a cascade of downstream effects on cognition.

Adult↗