Biomedical subjects

M M A Nielen

Publications and source records attributed to M M A Nielen.

4 recordsLinked to original sources

PubMed2004

Five-minute recordings of heart rate variability in obsessive-compulsive disorder, panic disorder and healthy volunteers.

BACKGROUND: Recent studies have used spectral analysis of heart rate variability (HRV) to study autonomous nervous system (ANS) function in panic disorder (PD). Most studies reported a reduced HRV in resting PD patients, suggesting increased sympathetic and decreased parasympathetic tone. In obsessive-compulsive disorder (OCD) inconsistent findings have been reported on ANS function and to date no studies have been carried out with spectral analysis of HRV. In this HRV study we compared ANS function in patients with PD, OCD and normal controls. METHODS: Standardized HRV measurement was carried out in 24 PD patients, 26 OCD patients and 24 age-matched normal controls. All patients were drug free. As this comparison yielded unexpected results, the PD and normal control samples were enlarged to 53 and 54 subjects, respectively, to verify our first measurement. RESULTS: OCD patients were not characterized by a reduced HRV, as compared to normal controls. This was also found in PD patients, even in the enlarged sample. CONCLUSIONS: HRV analysis in patients with OCD or PD showed that these patients were not characterized by ANS abnormalities, as no evidence was found of diminished HRV in a large sample of resting OCD and PD patients, measured sitting on a hospital bed.

Adult↗

PubMed2003

Neuropsychological investigation into the carcinoid syndrome.

RATIONALE: In patients suffering from metastatic carcinoid tumors, chronic disturbances of serotonergic metabolism are frequently present. Serotonin is supposed to influence a range of cognitive functions. OBJECTIVES: The present study evaluated the cognitive performance of carcinoid patients. METHODS: In 14 patients with proven carcinoid syndrome, neuropsychological functioning was studied. Visual search, sustained attention, set shifting ability and spatial working memory were assessed using tests from the CANTAB neuropsychological battery. This was compared with the performance of matched healthy controls. RESULTS: Plasma tryptophan levels were lower than controls. Patients showed an enhanced ability to learn new stimulus-response associations. Sustained visual attention, however, was impaired. CONCLUSION: Cognitive patterns were different from those found in depressive patients and partly mimicked those found in tryptophan depletion experiments. Further investigation has to point out the role of serotonergic changes in the accomplishment of affective states.

Aged↗

PubMed2003

Neuropsychological performance of OCD patients before and after treatment with fluoxetine: evidence for persistent cognitive deficits.

BACKGROUND: There is an ongoing debate about the nature of executive dysfunction that accompanies obsessive-compulsive disorder (OCD). One reason for this may be that state-related factors, such as use of medication or co-morbid symptoms, confound with task performance. This study tried to isolate trait- from state-dependent cognitive impairments by examining variability of cognition following treatment. METHOD: Nineteen OCD patients were tested on the Cambridge Neuropsychological Test Automated Battery (CANTAB) before and after treatment with fluoxetine. Their pattern of performance was compared to the one observed in healthy volunteers (N = 24). RESULTS: OCD patients displayed impairments in planning ability, spatial memory and motor speed that persisted after clinical improvement. With treatment, OCD performance diverged from that of controls on measures of focused attention and strategic ability. However, these effects were rather mild as they did not entail a significant deterioration of performance within the OCD sample. CONCLUSIONS: Our data suggest that cognitive impairments in OCD are not secondary to symptoms and therefore form a trait feature of the disorder. The nature of the deficits refers to a chronic dysfunction of the dorsolateral-striatal circuit. The minor effects of treatment on task performance is in line with recent evidence that serotonin mediates cognitive functions of orbitofrontal cortex to a greater extent than those associated with dorsolateral prefrontal regions.

Adolescent↗

PubMed2002

Decision making performance in obsessive compulsive disorder.

BACKGROUND: Neuro-imaging studies in OCD report the orbitofrontal cortex to be functionally abnormal. As these areas are presumed to be involved in decision making, studying this behavior in OCD may provide further insight into the cognitive deficits accompanying the disorder. METHODS: Performance of 27 drug-free OCD patients and 26 healthy volunteers was compared on the decision making task of Bechara et al. [Cognition, 50 (1994) 7-15]. RESULTS: OCD patients and volunteers displayed comparable decision-making behavior. Within OCD patients, risk taking was independently related to both anxiety and OCD severity. LIMITATIONS: Results must be regarded as preliminary, due to the limited number of OCD patients included and the lack of a clinical control group. CONCLUSIONS: Although VMpfc function is not generally impaired, it seems to be involved in OCD; possibly in another way than could be measured with this task. CLINICAL RELEVANCE: Clarification of cognitive distortions underlying OCD may guide development of new strategies for cognitive-behavioral therapy.

Adult↗