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Biomedical subjects

Edward H F de Haan

Publications and source records attributed to Edward H F de Haan.

At least 19 recordsLinked to original sources
PubMed2006

Seeing red primes tomato: evidence for comparable priming from colour and colour name primes to semantically related word targets.

There is ample evidence that an independent processing stream exists that subserves the perception and appreciation of colour. Neurophysiological research has identified separate brain mechanisms for the processing of wavelength and colour, and neuropsychological studies have revealed selective colour disorders, such as achromatopsia, colour agnosia, and colour anomia. The aim of the present study is to investigate whether the perception of colour may, despite its independent processing, influence other cognitive functions. Specifically, we investigate the possibility that the perception of a colour influences higher order processes such as the activation of semantically related concepts. We designed an associative priming task involving a colour prime (e.g. a red patch or the word RED) and a lexical decision response to a semantically related ('tomato' vs. 'timato') or unrelated ('grass' vs. 'griss') word target. The results of this experiment indicate that there is comparable facilitation of accessing colour-related semantics through the perception of a colour or the reading of a colour name. This suggests that colour has a direct effect on higher order level, cognitive processing. These results are discussed in terms of current models of colour processing.

Adult↗
PubMed2006

Perception of emotional facial expressions at different intensities in early-symptomatic Huntington's disease.

BACKGROUND: While there is abundant evidence that patients with Huntington's disease (HD) have an impairment in the recognition of the emotional facial expression of disgust, previous studies have only examined emotion perception using full-blown facial expressions. OBJECTIVE: The current study examines the perception of facial emotional expressions in HD at different levels of intensity to investigate whether more subtle deficits can be detected, possible also in other emotions. METHOD: We compared early symptomatic HD patients with healthy matched controls on emotion perception, presenting short video clips of a neutral face changing into one of the six basic emotions (happiness, anger, fear, surprise, disgust and sadness) with increasing intensity. Overall face perception ability as well as depressive symptoms were taken into account. RESULTS: A specific impairment in recognizing the emotions disgust and anger was found, which was present even at low emotion intensities. CONCLUSION: These results extend previous findings and support the use of more sensitive emotion perception paradigms, which enable the detection of subtle neurobehavioral deficits even in the pre- and early symptomatic stages of the disease.

Adult↗
PubMed2006

Covert colour processing in colour agnosia.

Patients with colour agnosia can perceive colours and are able to match coloured patches on hue, but are unable to identify or categorise colours. It is a rare condition and there is as yet no agreement on the clinical definition or a generally accepted explanation. In line with observations from object agnosia and prosopagnosia, we hypothesised that (some of) these patients might still be able to process colour information at an implicit level. In this study, we investigated this possibility of implicit access to colour semantics and colour names in a man (MAH) who suffers from developmental colour agnosia. We designed two experimental computer tasks: an associative colour priming task with a lexical decision response and a reversed Stroop task. The results of these experiments suggest that there is indeed automatic processing of colour, although MAH was unable to explicitly use colour information.

Adult↗
PubMed2006

Processing of emotional facial expressions in Korsakoff's syndrome.

Interpersonal contacts depend to a large extent on understanding emotional facial expressions of others. Several neurological conditions may affect proficiency in emotional expression recognition. It has been shown that chronic alcoholics are impaired in labelling emotional expressions. More specifically, they mislabel sad expressions, regarding them as more hostile. Surprisingly, there has been relatively little research on patients with Korsakoff's syndrome as a result of chronic alcohol abuse. The current study investigated 23 patients diagnosed with Korsakoff's syndrome compared to 23 matched control participants. This study is the first to make use of a newly developed sensitive paradigm to measure emotion recognition for several emotions (anger, disgust, fear, happiness, sadness and surprise). The results show that patients with Korsakoff's syndrome are impaired at recognizing angry, fearful and surprised facial emotional expressions. These deficits might be due to the reported sub-cortical brain dysfunction in Korsakoff's syndrome.

Adult↗
PubMed2006

Cognitive functions in carotid artery disease before endarterectomy.

Restorative effects of carotid endarterectomy (CEA) on cognitive functioning in patients with severe atherosclerotic disease presuppose the existence of cognitive deficits prior to the intervention. Thorough examination of this premise received only minor attention. The present study assessed symptomatic and asymptomatic patients with severe unilateral or bilateral stenosis of the carotid arteries one day before CEA. Healthy volunteers with similar demographic characteristics served as control subjects. Patients overall showed decreased functioning on tests of attention, verbal and visual memory, verbal fluency, and psychomotor speed and executive functioning, even after correction for the effects of mood. Simple motor skills and visuospatial functioning were not affected. Patients grouped according to presence and type of previous clinical symptoms and severity of contralateral stenosis only slightly differed from each other. The findings leave open the potential of improving cognitive function after CEA.

Aged↗
PubMed2006

Cognitive performance, psychological well-being, and brain magnetic resonance imaging in older patients with type 1 diabetes.

Modest cognitive impairment has been reported in young-adult patients with type 1 diabetes. In older patients with type 2 diabetes, cognitive impairments are more pronounced, which might be due to age but also to differential effects of type 1 diabetes and type 2 diabetes on the brain. This study therefore assessed cognitive performance and magnetic resonance imaging (MRI) of the brain in older type 1 diabetic patients. Forty type 1 diabetic patients (age >50 years) and 40 age-matched control subjects were included. Neuropsychological assessment included all major cognitive domains, and psychological well-being was assessed with questionnaires. Atrophy, white-matter abnormalities, and infarcts were rated on MRI scans. Type 1 diabetic patients performed slightly (effect sizes <0.4) worse on cognitive tasks, but only "speed of information processing" reached statistical significance. No significant between-group differences were found on any of the MRI parameters. Type 1 diabetic patients tended to report more cognitive and depressive problems than control subjects, but this did not correlate with the performance on cognitive tests. We conclude that cognition in older type 1 diabetic patients is only mildly disturbed. Chronic exposure to hyperglycemia is in itself, even at older age, apparently not sufficient to have considerable impact on the brain.

Aged↗
PubMed2005

Childhood-onset growth hormone deficiency, cognitive function and brain N-acetylaspartate.

Cognitive deficits have been reported in adults with childhood-onset growth hormone (GH) deficiency. We evaluated cognitive deficits simultaneously with parameters for neuronal integrity using (1)H magnetic resonance spectroscopy (MRS) in a cross-sectional design. We studied 11 adults (mean age 24.5 years) with childhood-onset GH deficiency, which persisted after reaching final height. All subjects were evaluated after interruption of GH supplementation for at least 3 months. We performed neuropsychological assessment (NPA) using tests evaluating memory, mental processing speed, reading ability and executive functioning. MRS was used to assess brain N-acetylaspartate (NAA)/choline ratios. Data were compared with an age-, sex- and education-matched control group (n=9, mean age 27.3 years). NPA demonstrated attenuated performance of the patients in the delayed verbal memory recall score (P<0.05) and the trail making A test (P<0.05), a measure of planning of behavior, processing speed and attention. Other neuropsychological tests were not affected. NAA/choline ratios were significantly reduced (P<0.01) in GH deficient subjects. Specific cognitive defects indicating affected memory and attention were found in patients with childhood-onset GH deficiency. These defects occur simultaneously with reduced neuronal integrity.

Adolescent↗
PubMed2005

Vascular risk factors and cognitive function in a sample of independently living men.

Decline of cognitive function with age may be due, in part, to atherosclerotic changes. The aim of the present study was to determine the relative contribution of vascular risk factors to cognitive functioning in a non-clinical sample of men. Cognitive tests were administered to 400 independently living men aged 40-80 years. The measures included short-term memory, speed of information processing, verbal and visual long-term memory, word fluency, cognitive flexibility, an estimate of verbal intelligence, and general cognitive status. Systolic blood pressure, serum cholesterol, glucose levels, smoking, alcohol intake, body mass index, homocysteine and peak expiratory flow rate were entered as independent variables into a multiple regression model, after adjustment for age and education. Hierarchical regression analyses revealed independent contributions of the combination of vascular risk factors in explaining the observed variance in performance on tests of cognitive functioning targeted at information processing capacity and speed and general cognitive status. Of the individual predictor variables, alcohol intake and homocysteine levels were significantly associated with processing capacity and speed, and peak expiratory flow rate was significantly associated with general cognitive status. Our results indicate that the combination of several independent vascular risk factors predicts performance on cognitive tests of information processing capacity and speed in a population-based sample of middle-aged and elderly men.

Activities of Daily Living↗
PubMed2005

The effects of type 1 diabetes on cognitive performance: a meta-analysis.

OBJECTIVE: To investigate the exact nature and magnitude of cognitive impairments in patients with type 1 diabetes and the possible association with other disease variables, such as recurrent episodes of hypoglycemia and metabolic control. RESEARCH DESIGN AND METHODS: MedLine and PsycLit search engines were used to identify studies on cognitive performance in patients with type 1 diabetes. Effect sizes (Cohen's d), which are the standardized differences between the experimental and the control group, were calculated. In the meta-analysis, a combined d value was calculated, expressing the magnitude of associations across studies. RESULTS: A total of 33 studies were identified that met the inclusion criteria. Compared with nondiabetic control subjects, the type 1 diabetic group demonstrated a significantly lowered performance on the following cognitive domains: intelligence (d = -0.7), speed of information processing (d = -0.3), psychomotor efficiency (d = -0.6), visual (d = -0.4) and sustained attention (d = -0.3), cognitive flexibility (d = -0.5), and visual perception (d = -0.4). Lowered cognitive performance in diabetic patients appeared to be associated with the presence of microvascular complications but not with the occurrence of severe hypoglycemic episodes or with poor metabolic control. CONCLUSIONS: In patients with type 1 diabetes, cognitive dysfunction is characterized by a slowing of mental speed and a diminished mental flexibility, whereas learning and memory are spared.The magnitude of the cognitive deficits is mild to moderate, but even mild forms of cognitive dysfunction might hamper everyday activities since they can be expected to present problems in more demanding situations.

Attention↗
PubMed2005

Faces retain attention.

In the present study, we investigated whether faces have an advantage in retaining attention over other stimulus categories. In three experiments, subjects were asked to focus on a central go/no-go signal before classifying a concurrently presented peripheral line target. In Experiment 1, the go/no-go signal could be superimposed on photographs of upright famous faces, matching inverted faces, or meaningful objects. Experiments 2 and 3 tested upright and inverted unfamiliar faces, printed names, and another class of meaningful objects in an identical design. A fourth experiment provided a replication of Experiment 1, but with a 1,000-msec stimulus onset asynchrony between the onset of the central face/nonface stimuli and the peripheral targets. In all the experiments, the presence of an upright face significantly delayed target response times, in comparison with each of the other stimulus categories. These results suggest a general attentional bias, so that it is particularly difficult to disengage processing resources from faces.

Attention↗
PubMed2005

Object versus spatial visual mental imagery in patients with schizophrenia.

OBJECTIVE: Recent research has revealed a larger impairment of object perceptual discrimination than of spatial perceptual discrimination in patients with schizophrenia. It has been suggested that mental imagery may share processing systems with perception. We investigated whether patients with schizophrenia would show greater impairment regarding object imagery than spatial imagery. METHODS: Forty-four patients with schizophrenia and 20 healthy control subjects were tested on a task of object visual mental imagery and on a task of spatial visual mental imagery. Both tasks included a condition in which no imagery was needed for adequate performance, but which was in other respects identical to the imagery condition. This allowed us to adjust for nonspecific differences in individual performance. RESULTS: The results revealed a significant difference between patients and controls on the object imagery task (F(1,63) = 11.8, p = 0.001) but not on the spatial imagery task (F(1,63) = 0.14, p = 0.71). To test for a differential effect, we conducted a 2 (patients v. controls) small ha, Cyrillic 2 (object task v. spatial task) analysis of variance. The interaction term was statistically significant (F(1,62) = 5.2, p = 0.026). CONCLUSIONS: Our findings suggest a differential dysfunction of systems mediating object and spatial visual mental imagery in schizophrenia.

Adult↗
PubMed2004

The functional neuroanatomy of metrical stress evaluation of perceived and imagined spoken words.

We hypothesized that areas in the temporal lobe that have been implicated in the phonological processing of spoken words would also be activated during the generation and phonological processing of imagined speech. We tested this hypothesis using functional magnetic resonance imaging during a behaviorally controlled task of metrical stress evaluation. Subjects were presented with bisyllabic words and had to determine the alternation of strong and weak syllables. Thus, they were required to discriminate between weak-initial words and strong-initial words. In one condition, the stimuli were presented auditorily to the subjects (by headphones). In the other condition the stimuli were presented visually on a screen and subjects were asked to imagine hearing the word. Results showed activation of the supplementary motor area, inferior frontal gyrus (Broca's area) and insula in both conditions. In the superior temporal gyrus (STG) and in the superior temporal sulcus (STS) strong activation was observed during the auditory (perceptual) condition. However, a region located in the posterior part of the STS/STG also responded during the imagery condition. No activation of this same region of the STS was observed during a control condition which also involved processing of visually presented words, but which required a semantic decision from the subject. We suggest that processing of metrical stress, with or without auditory input, relies in part on cortical interface systems located in the posterior part of STS/STG. These results corroborate behavioral evidence regarding phonological loop involvement in auditory-verbal imagery.

Acoustic Stimulation↗
PubMed2004

Effect of soy protein containing isoflavones on cognitive function, bone mineral density, and plasma lipids in postmenopausal women: a randomized controlled trial.

CONTEXT: Postmenopausal estrogen therapy has been posited to have some beneficial effects on aging processes, but its use has risks. Isoflavones, estrogenlike compounds naturally occurring in plant foods, might confer positive effects with fewer adverse effects. OBJECTIVE: To investigate whether soy protein with isoflavones improves cognitive function, bone mineral density, and plasma lipids in postmenopausal women. DESIGN, SETTING, AND PARTICIPANTS: Double-blind, randomized, placebo-controlled trial of 202 healthy postmenopausal women aged 60 to 75 years, recruited from a population-based sample in the Netherlands, conducted between April 2000 and September 2001. INTERVENTION: Participants were randomly assigned to receive 25.6 g of soy protein containing 99 mg of isoflavones (52 mg genistein, 41 mg daidzein, and 6 mg glycetein or total milk protein as a powder on a daily basis for 12 months. MAIN OUTCOME MEASURES: Cognitive function was assessed using the following instruments: dementia, Mini-Mental State Examination; memory, Rey Auditory Verbal Learning Test, immediate recall, delayed recall, and recognition, the Digit Span forward and reversed, and the Doors test; complex attention tasks, Digit Symbol Substitution and Trailmaking, A1, A2, and B; and verbal skills, Verbal Fluency A and N, animals and occupations, and the Boston Naming Task. Bone mineral density of the hip and lumbar spine was assessed using dual-energy x-ray absorptiometry scanning. Lipid assessment included lipoprotein(a), total cholesterol, low-density lipoprotein, high-density lipoprotein, and triglycerides. RESULTS: A total of 175 women completed the baseline and at least 1 postintervention analysis and were included in the modified intent-to-treat analysis. Adherence was good (median plasma genistein levels, 17.2 and 615.1 nmol/L for placebo and soy group, respectively). Cognitive function, bone mineral density, or plasma lipids did not differ significantly between the groups after a year. CONCLUSION: This double-blind randomized trial does not support the hypothesis that the use of soy protein supplement containing isoflavones improves cognitive function, bone mineral density, or plasma lipids in healthy postmenopausal women when started at the age of 60 years or later.

Bone Density↗
PubMed2004

Cerebral dysfunction in type 1 diabetes: effects of insulin, vascular risk factors and blood-glucose levels.

Type 1 diabetes can lead to several well-described complications such as retinopathy, nephropathy and peripheral neuropathy. Evidence is accumulating that it is also associated with gradually developing end-organ damage in the central nervous system. This relatively unknown complication can be referred to as "diabetic encephalopathy" and is characterised by electrophysiological and neuroradiological changes, such as delayed latencies of evoked potentials, modest cerebral atrophy and (periventricular) white matter lesions. Furthermore, individuals with type 1 diabetes may show performance deficits in a wide range of cognitive domains. The exact mechanisms underlying this diabetic encephalopathy are only partially known. Chronic metabolic and vascular changes appear to play an important role. Interestingly, the differences in the "cognitive profile" between type 1 and type 2 diabetes also suggest a critical role for disturbances of insulin action in the central nervous system.

Animals↗
PubMed2004

Functionally dissociated aspects in anterior and posterior electrocortical processing of facial threat.

The angry facial expression is an important socially threatening stimulus argued to have evolved to regulate social hierarchies. In the present study, event-related potentials (ERP) were used to investigate the involvement and temporal dynamics of the frontal and parietal regions in the processing of angry facial expressions. Angry, happy and neutral faces were shown to eighteen healthy right-handed volunteers in a passive viewing task. Stimulus-locked ERPs were recorded from the frontal and parietal scalp sites. The P200, N300 and early contingent negativity variation (eCNV) components of the electric brain potentials were investigated. Analyses revealed statistical significant reductions in P200 amplitudes for the angry facial expression on both frontal and parietal electrode sites. Furthermore, apart from being strongly associated with the anterior P200, the N300 showed to be more negative for the angry facial expression in the anterior regions also. Finally, the eCNV was more pronounced over the parietal sites for the angry facial expressions. The present study demonstrated specific electrocortical correlates underlying the processing of angry facial expressions in the anterior and posterior brain sectors. The P200 is argued to indicate valence tagging by a fast and early detection mechanism. The lowered N300 with an anterior distribution for the angry facial expressions indicates more elaborate evaluation of stimulus relevance. The fact that the P200 and the N300 are highly correlated suggests that they reflect different stages of the same anterior evaluation mechanism. The more pronounced posterior eCNV suggests sustained attention to socially threatening information.

Adult↗
PubMed2004

Anterior asymetrical alpha activity predicts Iowa gambling performance: distinctly but reversed.

Animal research indicates that the prefrontal cortex (PFC) plays a crucial role in decision making. In concordance, deficits in decision making have been observed in human patients with damage to the PFC. Contemporary accounts of decision making suggest that emotion guides the process of decision making by ways of providing for reward-punishment contingencies. A task capable of assessing the influence of reward and punishment on decision making is the Iowa gambling task. In this task decisions become motivated by inherent punishment and reward schedules. Insensitivity for punishment together with a strong reward dependency results in risk taking, which is in the gambling task the disadvantageous strategy. Interestingly, the processing of punishment and reward is argued to be lateralized over the right and left PFC, respectively. Here we investigated whether more relative left compared to right-sided frontal brain activity (left-sided dominance) quantified as reduced alpha (8-12 Hz) activity in the electroencephalogram (EEG) would lead to a more risky, disadvantageous pattern of decision making. Contrary to what was expected, relatively more right compared to left frontal brain activity was strongly associated with the disadvantageous strategy. The results are discussed in terms of recent theoretical accounts which argue that the functional interpretation of baseline frontal alpha activity depends on the mental operation involved and does not necessarily imply inactivity.

Adolescent↗
PubMed2004

The role of executive functioning in spontaneous confabulation.

OBJECTIVE: To follow the recovery course of a patient who exhibited an amnesic-confabulatory syndrome in conjunction with severe executive dysfunction in the first week following bithalamic infarction. BACKGROUND: Previous studies have shown that spontaneous confabulation originates from the combination of amnesia and executive dysfunction and that the degree of confabulation is determined by the degree of executive dysfunction. However, a few studies have also reported a dissociation between spontaneous confabulation and executive dysfunction. Therefore, the role of executive functioning in spontaneous confabulation is presently unclear. METHOD: Clinical examinations, magnetic resonance imaging (MRI), and cognitive and behavioral assessments with a focus on executive functions were conducted within the first week poststroke and after 6 months. RESULTS: MRI showed a bithalamic infarction involving the territory of the paramedian arteries predominantly affecting the dorsomedial and intralaminar nuclei of the thalami. Disappearance of spontaneous confabulation paralleled a specific recovery in mental flexibility, whereas all other executive components and long-term memory remained severely impaired at 6 months poststroke. CONCLUSIONS: Our case study provides additional evidence that mental flexibility, but not executive functioning in general, is a prerequisite for spontaneous confabulation. Direct or indirect functional deactivation of dorsolateral prefrontal cortex may be necessary for the development of spontaneous confabulation.

Amnesia↗