Eva Irle

Enlarged amygdala volume and reduced hippocampal volume in young women with major depression.

BACKGROUND Evidence is increasing that amygdala and hippocampus show significant structural abnormalities in affective disorders. Two previous studies found enlarged amygdala size in subjects with recent-onset major depression. METHOD Amygdala and hippocampal volumes were assessed in 17 young women with major depressive disorder and 17 healthy matched control subjects by use of three-dimensional structural magnetic resonance imaging. The severity of depressive symptoms was assessed using the Hamilton Depression Scale and the Beck Depression Inventory. RESULTS Compared with control subjects, depressive subjects had significantly larger (+13 %) amygdala volumes and significantly smaller (-12%) hippocampal volumes. Amygdala and hippocampal volumes were not significantly correlated with disorder-related variables. CONCLUSIONS Our results are consistent with previous findings of structural abnormalities of amygdala and hippocampus in subjects with recent-onset major depression. It may be suggested that the size of the amygdala is enlarged in the first years of the disorder, and may decrease with prolonged disorder duration.

Reduced size and abnormal asymmetry of parietal cortex in women with borderline personality disorder

BACKGROUND Evidence is accumulating that suggests borderline personality disorder (BPD) and posttraumatic stress disorder (PTSD) are related to small hippocampal size. Psychotic symptoms are frequent in both disorders. Psychotic spectrum disorders are known to be related to abnormalities of temporoparietal cortices. METHODS Using structural magnetic resonance imaging (3D-MRI), parietal cortex and hippocampal volumes were assessed in 30 young women with BPD who had been exposed to severe childhood sexual and physical abuse and in 25 healthy control subjects. RESULTS Compared with control subjects, BPD subjects had significantly smaller right parietal cortex (-11%) and hippocampal (-17%) volumes. The parietal cortex of borderline subjects showed a significantly stronger leftward asymmetry when compared with control subjects. Stronger psychotic symptoms and schizoid personality traits in borderline subjects were significantly related to reduced leftward asymmetry. Stronger trauma-related clinical symptoms and neuropsychologic deficits were significantly related to smaller hippocampal size. CONCLUSIONS Our results are consistent with previous findings of small hippocampal size in BPD and PTSD. Reduced right parietal cortex size in individuals with BPD may reflect a neurodevelopmental deficit of the right hemisphere.

Cerebellar lesions in the PICA but not SCA territory impair cognition

The authors sought to clarify whether lesions in different parts of the cerebellum result in differential cognitive and affective impairment. Six subjects with cerebellar lesions due to posterior inferior cerebellar artery (PICA) infarction, five subjects with lesions in the SCA vascular territory, and 11 matched controls were administered a battery of standard neuropsychological tests. PICA lesions but not SCA lesions resulted in cognitive and affective deficits pointing to a dominant role of posterior cerebellar regions in cognitive and affective processing.

Amygdala and hippocampal volumes and cognition in adult survivors of childhood abuse with dissociative disorders

Objective:  Trauma‐exposed individuals with post‐traumatic stress disorder (PTSD) display reduced amygdala and hippocampal size and impaired cognition. However, studies on trauma‐exposed individuals with dissociative amnesia (DA) or dissociative identity disorder (DID) are lacking.

Egocentric and allocentric memory as assessed by virtual reality in individuals with amnestic mild cognitive impairment

Present evidence suggests that medial temporal cortices subserve allocentric representation and memory, whereas egocentric representation and memory also depends on parietal association cortices and the striatum. Virtual reality environments have a major advantage for the assessment of spatial navigation and memory formation, as computer-simulated first-person environments can simulate navigation in a large-scale space. Twenty-nine patients with amnestic MCI (aMCI) were compared with 29 healthy matched controls on two virtual reality tasks affording to learn a virtual park (allocentric memory) and a virtual maze (egocentric memory). Participants further received a neuropsychological investigation and MRI volumetry at the time of the assessment. Results indicate that aMCI patients had significantly reduced size of the hippocampus bilaterally and the right-sided precuneus and inferior parietal cortex. aMCI patients were severely impaired learning the virtual park and the virtual maze. Smaller volumes of the right-sided precuneus were related to worse performance on the virtual maze. Participants with striatal lacunar lesions committed more errors than participants without such lesions on the virtual maze but not on the virtual park. aMCI patients later converting to dementia (n=15) had significantly smaller hippocampal size when compared with non-converters (n=14). However, both groups did not differ on virtual reality task performance. Our study clearly demonstrates the feasibility of virtual reality technology to study spatial memory deficits of persons with aMCI. Future studies should try to design spatial virtual reality tasks being specific enough to predict conversion from MCI to dementia and conversion from normal to MCI.

Reduced size of the pre-supplementary motor cortex and impaired motor sequence learning in first-episode schizophrenia.

Increasing evidence suggests that schizophrenia is associated with various morphological and functional abnormalities of the frontal cortex. So far research has concentrated on the dorsolateral and orbitofrontal cortex. Behavioral evidence suggests however that regions responsible for higher motor control are compromised in schizophrenia as well. The current study assessed volumes of the anterior supplementary motor area (pre-SMA) and implicit motor sequence learning in 15 subjects with first-episode schizophrenia and 15 healthy matched controls. Pre-SMA volumes were assessed by three-dimensional structural magnetic resonance imaging (3D-MRI) and manual parcellation according to an established protocol. Implicit motor sequence learning was assessed using the Serial Reaction-Time Task (SRTT). Compared with control subjects, schizophrenia subjects had significantly smaller volumes of the left pre-SMA (16%). Subjects with schizophrenia were severely impaired on sequence-specific implicit motor learning. Size of the left pre-SMA of schizophrenia subjects was significantly related to impaired implicit learning. We conclude that subjects with first-episode schizophrenia have a morphological abnormality of the left pre-SMA that might predispose them to develop disturbances of higher motor control during acute episodes of psychosis. These structural and behavioral abnormalities might be conceptualized within a broader model that views schizophrenia as a disorder of disturbed coordination of thought and action.

Differential impairments of facial affect recognition in schizophrenia subtypes and major depression

The goal of this study was to assess facial affect recognition abilities in subjects with various schizophrenia subtypes and subjects with major depression. A total of six disorganized, 21 paranoid and 18 residual subjects with schizophrenia (DSM-IV criteria) were compared with 21 subjects with major depression (DSM-IV criteria) and 30 matched healthy control subjects. Two experimental tasks requiring the sorting and rating of emotional facial expressions were applied. Disorganized and paranoid subjects showed strong impairments in the sorting of emotional facial expressions. Depressive subjects displayed only minor deficits, and residual subjects were unimpaired. Subjects with disorganized schizophrenia rated emotional facial expressions as more aroused, and depressive subjects rated them as less aroused, than the other study groups. Our study demonstrates strong deficits in facial affect recognition in subjects with schizophrenia and pronounced disorganized or psychotic symptoms. Deficits in facial affect recognition are specific to schizophrenia. They may be considered as a state marker of schizophrenia.

Implicit and explicit memory after focal thalamic lesions

Background: Lesions of the thalamus interfere with cognitive functions mainly in the area of declarative learning and memory. Little is known about the role the thalamus plays in implicit learning. Objective: To study explicit and implicit learning and memory in subjects with thalamic lesions and to analyze the influence of lesion characteristics on cognitive performance. Methods: The authors studied the performance of 15 subjects with focal thalamic infarction or hemorrhage on a comprehensive neuropsychological test battery focusing on tests of explicit memory and learning of a nondeclarative motor skill. Subjects with thalamic lesions were compared to 15 healthy matched control subjects and to a clinical control group of 22 subjects who had sustained basal ganglia lesions. Results: Subjects with thalamic lesions showed well-preserved intellectual and executive functions but demonstrated deficits on measures of attention and psychomotor speed, explicit memory, and implicit visuomotor sequence learning. Lesion size in the thalamus was clearly related to subjects’ long-term explicit memory performance. However, few of the neuropsychological deficits found seemed specific to the long-term neuropsychological outcome of focal thalamic infarctions. Subjects with lesions in the basal ganglia demonstrated similar deficits. Conclusions: Focal subcortical lesions in the thalamus and the basal ganglia lead to a similar profile of neuropsychological deficits. Lesions in the thalamus not only affect declarative memory but also interfere with nondeclarative motor skill learning.

Neuropsychological performance in frontal lobe epilepsy

The search for a special neuropsychological profile of frontal lobe epilepsy subjects (FLE) has so far led to inconclusive results. In this paper we compared the preoperative neuropsychological performance of FLE and temporal lobe epilepsy (TLE) subjects. We further investigated whether frontal lobe lesions of epileptogenic cause produce the same type of cognitive dysfunction as do tumours of the frontal lobe. Sixteen FLE subjects were compared to 16 TLE subjects as well as to a group of 10 subjects after the removal of frontal lobe tumors (TUM) and a healthy control group. A set of neuropsychological test measures routinely used for presurgical evaluation, an emotional conceptualization task and two associative learning tasks were administered. We found that subjects with frontal lobe damage were significantly impaired relative to controls on a wide range of cognitive functions independent of neurological cause. FLE subjects could hardly be discriminated from TLE subjects as both groups showed a similarly reduced level of neuropsychological performance. Our results demonstrate the devastating effect that frontal lobe epilepsy can have on cognitive functioning. Routinely used neuropsychological test measures lack the specificity to distinguish between frontal and temporal lobe epilepsy. Highly specialized measures are necessary to reveal differences.

Impaired and enhanced attentional function in children with attention deficit/hyperactivity disorder

BACKGROUND The symptom domain of inattention in attention deficit/hyperactivity disorder (ADHD) suggests that there are neuropsychological fields of attention in which subjects with ADHD express deficits. However, studies using differentiated neuropsychological attentional tests in ADHD are lacking. METHOD A consecutive series of 35 subjects with ADHD aged 9-12 years were assessed on a computer-driven neuropsychological test battery for attentional functions. Their performance was classified according to the data of a normative sample of 187 healthy subjects aged 9-12 years, and compared with the performance of 35 matched healthy control subjects. RESULTS According to normative data, most ADHD subjects performed on all attentional measures within the normal range. Comparisons with the control group revealed that ADHD subjects reacted faster on all attentional tests, yielding statistical significance for the Go/No go test and the Divided Attention test. They also performed with significantly fewer errors on the Divided Attention test. On the Go/No go test, Visual Scanning test and Attentional Shift test ADHD subjects committed significantly more errors than control subjects. CONCLUSIONS Our results suggest a differential pattern rather than a deficit pattern of attentional functions in ADHD. It is suggested that the more rapid response style of ADHD subjects leads to a more erroneous performance in self-paced attentional tasks and to a better performance in externally paced attentional tasks. However, neuropsychological tests of attention do not contribute to the clinical diagnosis of ADHD.