Biomedical subjects

Arve Asbjørnsen

Publications and source records attributed to Arve Asbjørnsen.

10 recordsLinked to original sources

PubMed2005

Frequency and characteristics of recurrent major depressed patients with unimpaired executive functions.

Major depression is associated with impairment of cognitive functions, and especially higher-order cognitive processes referred to as executive functions (EF). Whether this is a general finding is unclear. Patients without EF impairment may have different treatment needs than patients with EF impairment, and will probably have a better everyday functioning. Thus, it is important to identify the prevalence and characteristics of depressed patients without EF impairment. Forty-three patients with recurrent major depressive disorder (19-51 years) and 50 healthy controls were included in the study. The subjects were assessed with neuropsychological tests selected to measure central areas of EF, and screened on clinical and demographic variables. Within the depressed group, a total of 56% were defined as EF unimpaired. These patients were characterised by higher intellectual abilities and fewer depression episodes than the subgroup of patients with EF impairment. The subgroups were similar in age at debut of illness, severity of depression, general psychopathology and global level of functioning. In conclusion, about half of patients with recurrent major depression have normal EF. Since cognitive impairment and depressive symptomatology seem to be distinct dimensions, a neuropsychological investigation could help to ensure optimal treatment in patients with recurrent major depression.

Adult↗

PubMed2005

Validation of distinct amnesic and executive type memory deficit in a psychiatric sample based on retrieval performance.

Studies of localized brain dysfunctions have revealed connections between patterns of cognitive dysfunction and specific profiles of memory impairment. The amnesic type of memory impairment is defined by deficits in both free recall and recognition memory, whereas the dysexecutive memory impairment is characterized by retrieval deficits, i.e. a disproportional impairment in free recall relative to recognition memory. The present study tests whether classifications of psychiatric patients into recall impaired only (= RO group) and Recall and Recognition impaired (= RR group) correspond to the executive type and amnesic type of memory impairment. The alternative hypothesis is that the two groups merely differ in degree of neuropsychological and psychiatric disturbance. Forty-four subjects impaired on California Verbal Learning Test (CVLT) were selected from a larger database of 103 impaired and non-impaired subjects with schizophrenia or recurrent major depression. Subjects were classified into RO and RR groups and compared on measures of memory strategy (recency effect and interference on CVLT), overall neuropsychological function (Stroop Test and WAIS-R similarity) and psychiatric symptom load (positive and negative symptoms). Repeated measures ANOVA showed no effects of group, i.e. the RR group did not perform consistently below the RO group with regard to memory strategy, neuropsychological function or psychiatric symptom load. Two out of three analyses showed group x test interaction, supporting the dissociation of distinct executive and amnesic profiles among psychiatric patients. The RO group was more susceptible to interference but had better recency score than the RR group. The RO had higher negative symptoms while the RR group had higher positive symptoms.

Amnesia↗

PubMed2004

Early visual information processing in schizophrenia compared to recurrent depression.

Patients with schizophrenia have repeatedly shown deficits in early visual processing using backward masking (VBM) tasks. Whether this represents a specific dysfunction in schizophrenia is an unsolved question. Patients with recurrent unipolar depression represent an interesting comparison group to examine the question of specificity, but have never previously been assessed on VBM. In addition to comparing VBM performance in patients with schizophrenia and patients with depression, we wanted to examine the relations between VBM and clinical symptoms. Fifty-one patients with schizophrenia were compared to 49 patients with recurrent unipolar depression and 47 healthy controls. All subjects were administered a two-digit identification task in a no-masking and four masking conditions. Patients with schizophrenia performed significantly worse than normal controls on four of the five conditions. No significant difference was found between depression patients and normal controls. The effect of masking stimuli had no differential effects on the three groups. VBM correlated strongly with positive symptoms in the schizophrenia group.

Adult↗

PubMed2004

Digit span in dyslexia: variations according to language comprehension and mathematics skills.

The aim of this study was to investigate digit span performance in dyslexia. It was hypothesised that differences would be found in accordance with subgrouping by language comprehension and mathematic skills, and by analyses of how the digit span scores were attained. Two digit span tasks were given to a group of dyslexic children and controls (n = 57), mean age 12.62 (SD = 1.43). The tasks were "Digit Span" of the WISC-R, and "Digit Span 2," where the use of back-up strategies like finger counting and lip reading were restricted. As expected, the digit span scores were significantly lower in the dyslexia group than in the control group. Restrictions of back-up strategies did not alter the scores in the control group, while the scores were lowered in the dyslexia group. Further analyses of longest digit span, serial recall, and serial position indicated different retrieval patterns in the subgroups. The subgroup with good language comprehension and mathematic skills (n = 12), showed impaired serial recall especially in backward recall. The subgroup with good language comprehension skills, but with mathematics impairment (n = 9), showed impaired serial recall in both forward and backward recall. The subgroup with language impairments (n = 16), recalled fewer digits than the two other subgroups. The findings were discussed in relation to the "Phonological loop" of the Multi Component Model of Working Memory, and implications for intervention were discussed.

Adolescent↗

PubMed2004

Impairment across executive functions in recurrent major depression.

Depression is associated with impairment of cognitive functions, and especially executive functions (EFs). Despite the fact that most depressed patients experience recurrence of episodes, the pattern and the severity of executive impairment have not been well characterized in this group of depressed patients. We asked if and to what extent these patients were impaired on a range of neuropsychological tests measuring EFs, and also when confounding factors were adjusted for. Forty-five patients (aged 19-51 years) with moderate to severe (Hamilton score >18) recurrent major depressive disorder (DSM-IV) were compared to 50 healthy controls matched on age, education, gender and intellectual abilities. The subjects were administered a set of neuropsychological tests that assesses sub-components of EFs. The depressed patients were impaired compared to the control group on all selected tests, with a severity of impairment within -1 standard deviation from the control group mean. The group difference was statistically significant for eight of the 10 EFs that were assessed. These were measures of verbal fluency, inhibition, working memory, set-maintenance and set-shifting. The group difference was still significant for all sub-components except for set-shifting (Wisconsin Card Sorting Test) and planning (Tower of London), when additional medication and retarded psychomotor speed was adjusted for. In conclusion, the depressed subjects were mildly impaired across a wide range of EFs. This may have a negative impact on everyday functioning for this group of patients.

Adult↗

PubMed2004

Attentional functions in speech fluency disorders.

This study focused on attentional functions in fluency disorders. Nine persons who stuttered, eight persons who cluttered, and nine fluent controls, executed a set of attention tasks while psychophysiological indices of activation (heart rate variability and skin conductance) were recorded. The results indicated that the stutter group had a significantly longer response time on the Posner Test of Covert Attention Shifts than the other two groups, and the effect was most obvious when the target appeared in the right visual field. There were no significant differences between groups in the physiological activation as measured by heart rate, skin conductance and heart rate variability. The present results support the hypotheses that stuttering may be associated with impaired skills to focus attention, while cluttering did not seem to be associated with impaired focused attentional skills. However, the sample available within the study period was limited, and due to small samples care should be taken before making firm conclusions.

Adolescent↗

PubMed2004

Brain activation measured with fMRI during a mental arithmetic task in schizophrenia and major depression.

OBJECTIVE: The authors used functional magnetic resonance imaging (fMRI) to investigate brain activation in patients with schizophrenia and major depression while they performed two tasks-a vigilance task and a mental arithmetic task-that differed in cognitive complexity. METHOD: In the vigilance task, the participants had to press a response button whenever a specific number was seen on a screen inside the MR scanner. In the mental arithmetic task, the participants had to add two consecutive numbers and press the response button whenever the sum was 10. fMRI was performed with a 1.5-T MR scanner. Twelve patients with recurrent nonpsychotic unipolar major depression, 12 patients with schizophrenia, and 12 healthy comparison subjects were included in the study. RESULTS: Performance data showed that the patients were impaired relative to the comparison subjects and showed no difference in performance between the patient groups. The patients with schizophrenia, but not those with major depression, had less activation in prefrontal brain regions, relative to the comparison participants. However, subtracting brain activation during the vigilance task from activation during the mental arithmetic task showed that the schizophrenia patients had activation in parietal areas. CONCLUSIONS: A double dissociation of parietal and frontal lobe activation was found for the schizophrenia patients and the depression patients. The greater parietal lobe activation in the patients with schizophrenia may reflect a compensatory strategy for the failure to recruit cognitive processes that involve frontal lobe areas when solving a mental arithmetic task.

Adult↗

PubMed2003

Attentional and executive dysfunctions in schizophrenia and depression: evidence from dichotic listening performance.

BACKGROUND: We compared performance on a dichotic listening (DL) task between schizophrenic, depressed, and healthy control subjects. A variant of the traditional DL paradigm was used in which the subjects were required to focus attention either on the left (forced-left condition) or right (forced-right condition) ear stimulus. METHODS: The subjects were 51 patients with a DSM-IV diagnosis of schizophrenia, 49 patients with recurrent unipolar major depression, and 49 healthy control subjects. They were tested with a consonant-vowel syllables dichotic listening task under three attentional instructions. RESULTS: There was a significant overall right ear advantage during the nonforced condition, which increased dramatically during the forced-right condition and was eliminated during the forced-left condition. The depressed patients showed no signs of impairments compared with the healthy control group. Thus, they showed a right ear advantage during the nonforced and forced-right conditions, which was shifted to a left ear advantage during the forced left condition. The schizophrenic patients, however, were impaired on the forced-left condition compared with the healthy control and depressed subjects. CONCLUSIONS: The results are discussed in terms of separating attentional and inhibitory executive impairments in schizophrenia and depression, taking into consideration illness duration and information-processing demands.

Attention↗

PubMed2003

Visual-sequential and visuo-spatial skills in dyslexia: variations according to language comprehension and mathematics skills.

This study focused on visual-sequential and visuo-spatial functions in a group of 39 heavily dyslexic children, compared to a Control group. Mean age was 12.72 (SD 1.71). The dyslexia group was divided into three subgroups by language comprehension and mathematics skills. Only on a visual-sequential task was no difference seen between the groups. The main differences occurred between the two dyslexic subgroups with no language comprehension impairment, but with varying mathematics skills. Whereas the subgroup with good mathematics skills scored within the upper ranges, the mathematics-impaired subgroup showed significantly lower scores. The third dyslexic subgroup, with both language comprehension and mathematics impairments, performed within the norm. The study indicates a dissociation between language comprehension and visuo-spatial skills in dyslexia, which has implications for how variations in dyslexia should be understood. The results also show that the visuo-spatial impairments seen in one of the dyslexia subgroups lead to two ways of understanding mathematics impairment when it co-occurs with dyslexia: (1) as a visuo-spatial problem; (2) as a linguistic problem. These distinctions should imply different intervention strategies in dyslexia.

Adolescent↗

PubMed2003

Sensitivity and specificity of memory dysfunction in schizophrenia: a comparison with major depression.

Fifty-three schizophrenic subjects were compared to 50 patients with major depression and 50 normal controls on measures of working memory, declarative memory and malingering. The schizophrenic group scored 1-2 SDs below controls on all measures, while depressive patients exposed only lesser deficits in working memory and free recall. The memory deficit of the schizophrenic subjects was disproportionately greater than their intellectual decline. Differences between clinical groups could not be explained by differences in IQ, clinical symptom load or demographic characteristics. This indicates that impaired memory is a particular sensitive symptom of schizophrenia and that the impairment is specific to the illness. Working memory failure was prominent in both clinical groups. The schizophrenic subjects displayed primarily an acquisition failure, while the depressed group showed retrieval difficulties.

Adult↗