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W A van Gool

Publications and source records attributed to W A van Gool.

At least 73 records · Page 4Linked to original sources
PubMed1993

Ambulatory monitoring of tremor and other movements before and after thalamotomy: a new quantitative technique.

Tremor, e.g. in Parkinson patients, often shows large spontaneous fluctuations in severity over the day, to such an extent that a short observation is usually not sufficient to assess the overall severity or the effect of a treatment. Since momentary impressions of the tremor can thus be misleading, long-term ambulatory recordings would be helpful in the evaluation of severity and treatment effectiveness. As existing methods for long-term tremor registration have several shortcomings, a new method is proposed: an algorithm was designed to discriminate tremor from other movements and to describe the amount (i.e. the proportion of tremor or movements per time unit) as well as the intensity (i.e. average acceleration amplitude) of the two types of movement. In the evaluation of the severity of tremor both the amount and intensity of tremor episodes are of importance. The algorithm was tested on 24-h analog tape recordings of wrist-movement in 10 young and 10 aged controls, as well as in 8 patients with tremor--both before and after a tremor relieving thalamotomy. The algorithm scored movements as 'tremor' exclusively in patients prior to the operation. Fluctuations in tremor severity over the day were detected, and tremor could be discriminated from non-pathological movements. Moreover, following thalamotomy, motor slowing (bradykinesia) was detectable using this algorithm. Based on these test results, a miniaturized device in wrist-watch format is now being developed for long-term registrations.

Adult↗
PubMed1992

[Studies of cerebrospinal fluid diagnosis in Alzheimer's disease: a review of the literature and of current developments].

Studies into the value of examination of the cerebrospinal fluid (CSF) in diagnosing Alzheimer's disease are reviewed. The diagnostic utility of about 60 substances including CSF measures related to classical neurotransmitters, (neuro)peptides, proteins, amino-acids, trace elements, and constituents of senile plaques and neurofibrillary tangles is evaluated. Technical, methodological, and ethical issues relevant to this kind of studies are discussed. None of the CSF constituents studies so far, has a proven diagnostic utility. Increased knowledge concerning macromolecular changes in the brain and improved immunochemical techniques make the outlook for a diagnostic test for Alzheimer's disease on CSF promising.

Alzheimer Disease↗
PubMed1991

Tetrahydroaminoacridine and lecithin in the treatment of Alzheimer's disease. Effect on cognition, functioning in daily life, behavioural disturbances and burden experienced by the carers.

In 12 ambulant patients with a clinical diagnosis of probable Alzheimer's disease, a 12-week, double-blind, placebo-controlled study with 100 mg/day tetrahydroaminoacridine (THA) and 10 g/day lecithin is reported. The aim of the study was to find whether treatment would result in an improvement of cognition, of functioning in daily life, decrease of behavioural disturbances, and decrease in burden experienced by the carers. Two of the six THA-treated patients demonstrated an increase on cognitive test scores with a moderate increase in the other outcome measurements. There was, however, no difference between the two groups in any outcome measurement after treatment. In addition, we found a reversible rise of liver transaminases in 4 of 6 patients in the treated group. This pilot study is too small to draw definite conclusions on the use of THA alone or in combination with lecithin. Our results suggest, however, that semi-structured interviews with the carers may be of value in the evaluation of treatment effects in patients with Alzheimer's disease.

Aged↗
PubMed1991

Cerebrospinal fluid markers of Alzheimer's disease.

OBJECTIVE: To review studies on cerebrospinal fluid (CSF) in patients with Alzheimer's disease (AD) in order to answer the question whether CSF contains a specific marker which can be used to support a clinical diagnosis of AD. DATA SOURCES: Studies identified through an English-language literature search using MEDLINE (1966 to 1990) and a review of bibliographies of relevant articles. STUDY SELECTION: All studies on CSF in AD patients were selected. Double publications on the same original data were not included. Otherwise, no particular selection was made. DATA EXTRACTION: The diagnostic utility of more than 60 substances, including CSF measures related to classical neurotransmitters, (neuro)peptides, proteins, amino acids, purines, trace elements, and constituents of senile plaques and neurofibrillary tangles, is evaluated. Clinical epidemiological criteria for deciding on the usefulness of new diagnostic methods are emphasized in this analysis. DATA SYNTHESIS: Concentrations of some CSF constituents are consistently found to be significantly changed in AD. However, overlap with data of control populations and methodological shortcomings in study design, limit the diagnostic value of all CSF measurements reviewed. CONCLUSIONS: None of the CSF constituents studied so far can be used in support of the diagnosis of AD. However, increased knowledge concerning macromolecular abnormalities in amyloid containing plaques and neurofibrillary tangles makes the outlook for a diagnostic test for AD on CSF promising.

Alzheimer Disease↗
PubMed1991

[CAMDEX-N: the Dutch version of the Cambridge Examination for Mental Disorders of the Elderly with automatic data processing].

In the study of dementia four distinct categories of instruments can be distinguished: instruments to examine cognitive dysfunction, to measure the severity of dementia, to assess disturbances in daily behaviour, and instruments to make a differential diagnosis of dementia. The Cambridge Examination for Mental Disorders of the Elderly (CAMDEX), published in 1988, incorporates these four categories in a single comprehensive interview schedule. Items related to the diagnosis of clouded/delirious state, depression and other psychiatric symptoms are also included. The Dutch version (CAMDEX-N) and accompanying software for data analysis and for scientific research were developed. Items were added to the section on physical and neurological examination, and to the section on ancillary investigations. The software can be adapted to future developments in dementia research.

Aged↗
PubMed1987

Age-related changes in circadian sleep-wakefulness rhythms in male rats isolated from time cues.

Sleep-wakefulness rhythms were recorded for at least 5 consecutive days in young adult (n = 6; 5-8 months) and old (n = 4; 30-32 months) rats. During the continuous recordings the rats were maintained in isolated cabins under constant temperature and constant dim, red light. The period length and amplitude of the free-running circadian rhythms of wakefulness (W), slow wave sleep (SWS) and desynchronized sleep (DS) were estimated by means of a cosine curve fitting program. Age-related amplitude differences were absent under the constant recording conditions. The circadian period of the W- and DS-rhythms, however, was significantly shorter in the old rats. These results are consistent with the notion that circadian organization is changed in old age.

Aging↗
PubMed1987

Changes in vasopressin cells of the rat suprachiasmatic nucleus with aging.

The suprachiasmatic nucleus (SCN) of the hypothalamus is considered to be the endogenous clock of the mammalian brain, regulating circadian rhythmicity of a great number of physiological and behavioural parameters. Numerous studies have shown that the circadian organization in the rat is progressively disturbed in senescence. However, a recent study by Peng et al.17 using conventionally stained material, revealed no decrease in overall SCN cell number of senescent rats. Their results have now been confirmed in this study. In addition, an increase in SCN volume (P = 0.02) and nucleus diameter (P = 0.001) and an overall decrease in cell density (P = 0.006) was observed. All these parameters seem to confirm the absence of a general degeneration in the senescent SCN. However, the major aim of the present study was to determine whether a well-defined population of neurons, i.e. the vasopressinergic (AVP) cells of the SCN, shows changes with aging. Immunocytochemical staining with antivasopressin and morphometry revealed a decrease of 31% (P = 0.007) in the number of these SCN neurons, whereas the remaining vasopressin cells became larger (P = 0.001). There were no statistical significant differences between rats housed in standard cages and those housed in an enriched environment in either age group, but the groups were relative small. Changes in either the number or stainability of SCN vasopressin neurons may be a morphological correlate of changed circadian rhythms in senescence.

Aging↗
PubMed1986

Visual and auditory evoked potentials in different areas of rat cerebral cortex.

Visual and auditory evoked potentials were studied in the occipital, temporal, prefrontal and cingulate areas of the rat cerebral cortex. We found that both prefrontal and cingulate areas can respond to more than one sensory modality. The latencies of the response to light and sound, though slightly longer in these associative areas than in the two primary cortical regions, were still within the range of early sensory evoked responses (i.e. less than 50 ms).

Acoustic Stimulation↗
PubMed1986

Effects of aging and housing in an enriched environment on sleep-wake patterns in rats.

The effects of aging and housing in an enriched environment were assessed in young adult (4-7 months) and old (27-31 months) male Brown Norway rats by conducting 24-h sleep-wake recordings. Comparison of recordings made in rats of different ages, housed in a standard laboratory environment, revealed a reduction of the time spent in slow wave and desynchronized sleep during the light period in the old rats. Furthermore in the old rats, sleep was more fragmented and the amplitude of the circadian sleep-wake rhythm was reduced. In both age groups, housing in an enriched environment resulted in an increase of the time spent in slow wave and desynchronized sleep during the light period. Old "enriched" rats showed an additional alleviation of the senescence-related shortening of sleep cycles and desynchronized sleep epochs. The reduction of the circadian sleep-wake amplitude observed in old age was, however, not affected by the differential housing period. It is concluded that the similarity of the changes in sleep pattern in young and old rats after increased environmental complexity may reflect a preserved capacity of the senescent nervous system to adapt to environmental changes.

Adaptation, Biological↗
PubMed1985

Spatial memory and visual evoked potentials in young and old rats after housing in an enriched environment.

The effects of aging and of housing in an enriched environment on performance in an 8-arm radial maze were evaluated in young adult (7-8 months) and old (30-33 months) male Brown-Norway rats, using a procedure in which the rats were confined for 8 s to the central platform of the maze between consecutive choices. Although the old rats attained a level of performance which was clearly above change, they were shown to perform worse than the young rats. No performance differences were found between differentially housed rats of the same age group. In a second experiment recovery cycles of visual evoked potentials were determined in the same rats by using paired flashes with an interstimulus time of 400, 300, 200, or 100 ms. Recovery was consistently smaller in the old rats as compared to the young ones. No correlation could be demonstrated, however, between radial maze performance or housing condition and recovery functions of the visual evoked potentials. This finding indicates that a decline in visual sensitivity cannot readily explain the impaired radial maze performance of old rats. Evidence which suggests that age-related hippocampal changes play a major role in the radial maze performance deficit is discussed.

Age Factors↗
PubMedDate not supplied

Determinants of global clinical change assessment in patients with early Alzheimer's disease.

Global clinical impression (GCI) of change is assumed to integrate aspects of both cognitive and noncognitive functioning. We evaluated 140 consecutive patients with probable (n = 90) and possible (n = 50) early Alzheimer's disease at baseline and after 6 months with measurements of global cognitive function (CAMCOG), behavior, activities of daily living, and burden of the caregiver. After 6 months, both the clinician (GCI-clin) and the caregiver (GCI-care) rated clinical change on a 3-point scale (worse, no change, improved). Data were analyzed with multiple polychotomous logistic regression, adjusted for age and sex. Change in global cognitive function and GCI-care were significantly and independently related to GCI-clin, while changes in activities of daily living and in behavior were significantly and independently associated with GCI-care. The findings suggest a double dissociation. Change in cognition appears to be the major determinant of the clinician's global impression but not change in behavioral and functional parameters, while global impression of the caregiver is primarily based on change in behavioral and functional measures but not on change in cognition.

Activities of Daily Living↗