Biomedical subjects

B Fimm

Publications and source records attributed to B Fimm.

7 recordsLinked to original sources

PubMed2006

Influence of a 30-min break on divided attention and working memory in resident anaesthetists on daily routine.

BACKGROUND: The aim of this study is to test the hypothesis that a standard 30-min break in a routine 7.5 h period of work makes a difference in cognitive function. METHODS: In a double-blinded, cross-over trial 30 residents in anaesthesia were randomized to receive or not to receive a 30-min break between the assessment times of 07:30 and 14:00. in a normal working day. After at least 28 days the test was repeated with each resident in the opposite group. Primary outcome measure was the Test for Attentional Performance with the subtest of working memory and divided attention. Secondary outcomes are the Stanford Sleepiness Scale and the State-Trait Anxiety Inventory test. RESULTS: The sleep, caffeine and nicotine habits in both groups were comparable. There was no difference between the two groups in the Test for Attentional Performance, Stanford Sleepiness Scale and the State-Trait Anxiety Inventory. The correlation between recovery through sleep and sleep disturbance in the night before investigation to the Stanford Sleepiness Scale (P<0.001 and P=0.003) and State-Trait Anxiety Inventory (P<0.001 and P=0.001) at the 07:30 assessment is significant. For the 14:00 assessment the only significant correlation is between the recovery through sleep with the Stanford Sleepiness Scale (P=0.04) and the State-Trait Anxiety Inventory (P=0.05). CONCLUSION: A 30-min break during a 7.5 h daily routine did not influence cognitive function tests.

Adult↗

PubMed2006

The effect of low arousal on visuo-spatial attention.

Clinical and experimental evidence suggests a special role of the right hemisphere for alerting and orienting. However, it is not clear whether these attentional aspects should be taken to be independent or interacting. At least on the functional neuroanatomical level there seems to be an overlap in right parietal and frontal cortical structures. In this sleep deprivation study we examined the effect of different levels of arousal on covert orienting of attention repeatedly over a period of 28 h in 11 healthy subjects. The main finding is a disproportionate and significant slowing of responses to stimuli presented to the left visual hemifield that could only be observed in a state of maximally reduced arousal at 5:00 a.m. Furthermore, a facilitation of attentional shifts to the right could be observed in invalid trials when attention had to be reoriented. These results suggest an interaction of arousal and orienting, at least in situations of maximally reduced activation when attentional asymmetries could be provoked even in healthy subjects. The findings are compatible with a right hemisphere dominance for alerting and orienting, and they are discussed in the light of theoretical accounts of visual orienting.

Adult↗

PubMed2005

Spatial attention: more than intrinsic alerting?

It has been proposed that the right hemisphere alerting network co-activates, either directly or via the brainstem, the attention system in the parietal cortex involved in spatial attention. The observation that impaired alertness and sustained attention can predict the outcome of neglect might suggest such a relationship, too. In the present fMRI study, we intended to analyse and compare the functional anatomy of two attentional conditions both involving intrinsic (endogenous) alerting and fixation but differing with respect to the degree of spatially distributed attention by using the same paradigm under two different attentional conditions. In a group of ten participants, both a focused and a distributed visuospatial attention condition evoked similar patterns of activation in dorsolateral prefrontal regions, in the anterior cingulate gyrus, in the superior and inferior parietal cortex as well as in the superior temporal gyrus and in the thalamus. These activation foci were stronger in the right hemisphere under both conditions. After subtraction of the alertness condition with focused spatial attention, distributed spatial attention with stimuli appearing at unpredictable locations within both visual fields induced additional bilateral activations only in the left and right superior parietal cortex and in the right precuneus suggesting that these regions are specific for a more widespread dispersion of spatial attention.

Adult↗

PubMed2001

Asymmetries of visual attention after circumscribed subcortical vascular lesions.

OBJECTIVE: To investigate the role of the basal ganglia and the thalamus for basic processes of visuospatial attention METHODS: Fifteen patients with acute circumscribed vascular lesions (10 with haemorrhage and five with infarction) were included in the study. The lesions were confined exclusively to subcortical structures, such as the basal ganglia, internal capsule, and thalamus, which was confirmed by initial CT on the day of referral and MRI taken 14-28 days after clinical onset. These patients were examined with two computerised attentional tasks (one detection and one search task) measuring spatial visual attention. RESULTS: There was a clear attentional asymmetry in patients with right hemispheric lesions (RHLs) in the visual search task. Seven out of eight patients with RHLs tended to be slower and/or missed significantly more target stimuli in the left sided part of a stimulus array consisting of 25 small squares than in right sided parts, although none of these patients showed signs of visual hemineglect in the visual detection task presenting visual information simultaneously to the right and left visual hemispace. All but one of these patients showed lesions in the posterior limb of the internal capsule and the putamen. On the other hand, patients with left hemispheric lesions were not impaired in the search task with only one patient showing more contralesional omissions of target stimuli than could be expected from the behaviour of normal controls. CONCLUSIONS: The results are in line with previous results showing a dominant role of right hemispheric neuronal structures for spatial attention. Furthermore, the data suggest that even with right hemispheric subcortical lesions without cortical involvement deficits in spatial orienting of attention to the left hemispace can be seen. These asymmetries of visual attention in the absence of neglect symptoms are supposed to be caused (1) by a disruption of the motor corticostriato-pallidothalamo-cortical neuronal circuit or (2) by a (partial) disconnection of relevant parts within the posterior attention network-namely, parietal and thalamic structures.

Adult↗

PubMed2000

Impaired cognitive performance in drug free users of recreational ecstasy (MDMA)

OBJECTIVES: Ecstasy (3,4-methylenedioxymethamphetamine (MDMA) and related congerers: MDA, MDEA) is the name given to a group of popular recreational drugs. Animal data raise concern about neurotoxic effects of high doses of ecstasy on central serotonergic systems. The threshold dose for neurotoxicity in humans is not clear and serotonin is involved in several functions including cognition. The purpose of this study was to investigate cognitive performance in a group of typical recreational ecstasy users. METHODS: A comprehensive cognitive test battery was administered to 28 abstinent ecstasy users with concomitant use of cannabis only and to two equally sized matched groups of cannabis users and non-users. The sample consisted of ecstasy users with a typical recreational use pattern and did not include very heavy users. RESULTS: Ecstasy users were unimpaired in simple tests of attention (alertness). However, they performed worse than one or both control groups in the more complex tests of attention, in memory and learning tasks, and in tasks reflecting aspects of general intelligence. Heavier ecstasy and heavier cannabis use were associated with poorer performance in the group of ecstasy users. By contrast, the cannabis users did not differ significantly in their performance from the non-users. CONCLUSIONS: The present data raise concern that use of ecstasy possibly in conjunction with cannabis may lead to cognitive decline in otherwise healthy young people. Although the nature of the emerging cognitive disturbance is not yet clear, an impairment of working memory might be the common denominator underlying or contributing to declines of performance in various tasks. The cognitive disturbance is likely to be related to the well recognised neurotoxic potential of ecstasy. The data suggest that even typical recreational doses of ecstasy are sufficient to cause neurotoxicity in humans.

Adolescent↗

PubMed1994

Different mechanisms underly shifting set on external and internal cues in Parkinson's disease.

A set shifting task consisting of the comparison of two digits according to their numerical value or their form guided by an explicit (external cue) or implicit (internal cue) rule was performed by 8 untreated and 19 treated patients suffering from Parkinson's disease (PD) and 15 control subjects. The subjects could not predict the number of trials for a given target. The treated PD patient group exhibited increased post-shift error rates under the internal cue condition. In the external cue condition, only the untreated patients produced more errors when shifting to a new response criterion. Reaction times were prolonged in treated PD patients, irrespective of type of cue. Large interindividual variability within the patient groups is considered as meaningful and indicates individual differences in the neuropsychological impairment and/or the neurotransmission deficit. Pathophysiological and neuropsychological impairments underlying these findings are discussed on the basis of the models of Penney and Young (1983/1986) and Norman and Shallice (1980/1986).

Aged↗

PubMed1992

Cognitive slowing in decision tasks in early and advanced Parkinson's disease.

Ten untreated patients with recently diagnosed Parkinson's disease (PD), 9 treated patients with more advanced pathology, and 17 matched normal controls were investigated with three reaction tasks with increasing cognitive load but identical motor requirements: simple reaction, choice reaction with indicative stimuli, and choice reaction with ambiguous stimuli. Times required until a home key was released (= reaction time) and from then until a response key was pressed (= movement time) were recorded. Estimates of pure decision time (overall response time minus movement time in a simple reaction time task) revealed a difference between advanced and early PD patients. Advanced PD patients showed an overall slowing of decision time in the reaction time tasks, but the effect of the cognitive load of the tasks on the decision time was comparable to a control group. The untreated early PD patients performed quite normally in the more simple decision tasks but showed a disproportionate slowing of decision time in tasks with higher cognitive load.

Adult↗