Biomedical subjects

Nils Inge Landrø

Publications and source records attributed to Nils Inge Landrø.

12 recordsLinked to original sources

PubMed2006

Norwegian norms and factor-structure of phonemic and semantic word list generation.

Word list generation (WLG) tasks are used world wide as measures of executive function, although the tests are sensitive also to deficits in other cognitive functions. Norms derived from English-speaking samples are often used in Norway, even though the consequences of language differences are not yet been assessed. The reliability of WLG testing in Norway is increased by the norms presented in the first part of the study. The validity of WLG tests as measures of executive function is addressed in the second part, by performing a factor-analysis of neuropsychological performance in a mixed psychiatric sample. Education contributed most to performance. There were no sex-differences in overall performance. Factor analysis indicated that phonemic WLG is a more specific measure of executive function than semantic WLG. Semantic WLG correlated higher with basal processing speed, thus being more sensitive to aging. In conclusion the clinical neuropsychologist is advised to control for reduction in basal processing speed before interpreting WLG scores as specific deficits in executive function. The Norwegian norms correspond well with most comparable studies in other languages, thus failing to show any language specific effects.

Adolescent↗

PubMed2006

Opioid switching from oral slow release morphine to oral methadone may improve pain control in chronic non-malignant pain: a nine-month follow-up study.

Twelve patients with poor pain control or unacceptable side effects during treatment with morphine were switched to methadone and followed for nine months in this open prospective study. Primary outcomes were patient preference for opioid and pain control while physical, cognitive and role functioning were secondary outcomes. The morphine dose was decreased by 1/3 daily and was replaced with an equianalgesic dose of methadone over a three-day period. During switching and a one-week dose titration period, patients were given additional methadone if required. During dose titration one patient experienced sedation requiring naloxone. Four patients were switched back to morphine due to poor pain control, drowsiness or sweating. Seven patients preferred long-term (>nine months) treatment with methadone and reported reduced pain and improved functioning while cognition was not improved. This study brings novel information on the long-term consequences for pain control, health-related quality of life and cognitive functioning with a switch from morphine to methadone in the treatment of chronic non-malignant pain.

Administration, Oral↗

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

Cognitive functioning in adolescents with schizophrenia spectrum disorders.

In contrast to studies of cognitive functioning in adults with schizophrenia, there has been a relative paucity of studies assessing adolescents with schizophrenia. We investigated cognitive functioning in 22 adolescents with schizophrenia spectrum disorders compared with 30 healthy adolescents. The patient group demonstrated impaired performance on all of the functions investigated except sustained attention. Against the background of this broad impairment, executive function and psychomotor speed were the most impaired, sustained attention was spared, while preattentional processing, early visual information processing, visual long-term memory, auditory short-term memory and working memory emerged as relative deficits. The study shows that adolescents with schizophrenia spectrum disorders demonstrate a similar pattern of cognitive functioning to adults in all areas, except sustained attention.

Adolescent↗

PubMed2004

Depressive symptoms account for deficient information processing speed but not for impaired working memory in early phase multiple sclerosis (MS).

Depressive symptoms may influence neuropsychological functioning negatively. A substantial proportion of multiple sclerosis (MS) patients exhibit neuropsychological impairments and depressive symptomatology is more common in MS as compared to healthy controls and to other neurological diseases. The objectives of the present study were to assess information processing speed, working memory and executive functions in early phase MS and to investigate whether severity of depressive symptoms account for these aspects of cognition in MS. The patients show slowed information processing speed and impaired working memory, whereas executive functioning, as measured with the Wisconsin Card Sorting Test, is unaffected. Depressive symptoms account for slowed information processing speed, but not for impaired working memory.

Adult↗

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

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

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↗

PubMed2002

Lowering of serotonin by rapid tryptophan depletion increases impulsiveness in normal individuals.

RATIONALE: Reduced serotonergic activity has been associated with impulsive behavior; however, intervention studies have been scarce. OBJECTIVES: To examine whether induced lowering of serotonin (5-HT) levels would increase behavioral measures of impulsivity. METHODS: Twenty-four healthy young males ingested a mixture of the essential amino acids except for tryptophan in a balanced, randomized, double-blind, placebo-controlled, cross-over study design. The continuous-performance test-identical pairs was administered when the plasma concentration of tryptophan was expected to be at the lowest point. The plasma concentrations of 23 amino acids were measured at baseline and 5 h after the ingestion of the amino acid mixture. RESULTS: The intervention led to a dramatic fall in free and total plasma tryptophan, and the tryptophan/large neutral amino acids ratio. This in turn has been shown to lower the level of 5-HT in the central nervous system. The tryptophan depletion resulted in a statistically significant more impulsive- or disinhibited response style on the continuous-performance test-identical pairs when the subjects were solving verbal tasks. Depleted subjects exposed to spatial stimuli had fewer correct responses and a decreased ability to discriminate between stimuli. CONCLUSIONS: These results indicate that a rapid lowering of tryptophan increases impulsiveness and decreases discriminating ability in normal individuals. The effect of 5-HT depletion on discriminating ability in this study was similar to that previously reported in depressed patients.

Adult↗