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Biomedical subjects

J H van den Bercken

Publications and source records attributed to J H van den Bercken.

9 recordsLinked to original sources
PubMed1997

The contribution of risk factors to the effect of early otitis media with effusion on later language, reading, and spelling.

A cohort of 946 children who were screened for otitis media with effusion (OME) from the ages of 2 to 4 were studied for language, reading, and spelling at 7 years of age. The effects of OME in combination with single risk factors and with increasing numbers of risk factors were investigated. An interaction with an additional risk factor was found only for gender and OME, with boys' spelling influenced negatively by a history of OME. OME in combination with preterm birth and low birthweight also appears to put children at risk for later language and educational problems. Although a negative linear relation between the number of risk factors and later functioning was found, it is suggested that OME, even when combined with a number of other risk factors, produces only minor effects on later language, reading, and spelling.

Child↗
PubMed1997

Experienced consent in geriatrics research: a new method to optimize the capacity to consent in frail elderly subjects.

OBJECTIVES: Cognitive and sensory difficulties frequently jeopardize informed consent of frail elderly patients This study is the first to test whether preliminary research experience could enhance geriatric patients' capacity to consent. DESIGN/SETTING: A step-wise consent procedure was introduced in a study on fluid balance in geriatric patients. Eligible patients providing verbal consent participated in a try-out of a week, during which bioelectrical impedance and weight measurements were performed daily. Afterwards, written informed consent was requested. Comprehension, risk and inconvenience scores (ranges: 0-10) were obtained before and after the try-out by asking ten questions about the study's essentials and by asking for a risk and inconvenience assessment on a ten-points rating scale. SUBJECTS AND RESULTS: Seventy of the 78 eligible subjects started the try-out and 53 (68%) provided written consent. The comprehension score increased from 5.0 (+/- 2.3) to 7.0 (+/- 1.9) following the try-out (P < 0.001). The number of subjects capable of weighing risks and inconveniences increased from 32 to 48 (P < 0.001). CONCLUSIONS: Research experience improved the capacity to consent, still enabling an acceptable participation rate. Therefore, experienced consent seems a promising tool to optimize informed consent in frail elderly subjects.

Aged↗
PubMed1992

Diagnostic classification by experts and novices.

The present study examines differences between experts and novices in classifying symptoms and the effect of the nature of the task on classifying. The study involved three groups of subjects, two expert groups (n = 12, n = 10) and one novice group (n = 12). Thinking-aloud protocols were collected for two classification tasks: sorting of behavioural symptoms into predefined categories and intuitive clustering of behavioural symptoms. In a third task, experts and novices were asked to make typicality ratings of behavioural symptoms. The protocols were analyzed with respect to seven cognitive operations: (a) asking or giving information, (b) associating, (c) abstracting or labelling, (d) explaining, (e) neutral matching, (f) identifying, and (g) differentiating. Results showed an effect of experience and an effect of the task on the relative frequencies of these operations. No differences were found in typicality rating of experts versus novices. These contradictory findings are discussed in relation to Kolodner's model about the evolution of expertise.

Behavior↗
PubMed1990

Bimanual simultaneous motor performance and impaired ability to shift attention in Parkinson's disease.

The ability to share time and to shift attention between bimanual simultaneous motor tasks were studied in 18 patients with Parkinson's disease (PD) and 19 age- and intelligence-matched controls. The task consisted of drawing triangles with the dominant hand and squeezing a rubber bulb with the nondominant hand. Motor performance was measured using the variables: amplitude of squeezing, frequency of squeezing and velocity of drawing triangles. After eliminating variance due to baseline differences in single-handed performance, the bimanual simultaneous performance of PD and controls turned out to be similar to the frequency of squeezing and the velocity of drawing triangles. The amplitude of squeezing, however, differed between the two groups: it was significantly reduced in PD. Arguably the disturbance in the bimanual performance of PD patients was not due to a disorder of time sharing, but to a decreased ability to shift attention from the visually cued task to the non visually cued task. The results agree with current evidence that PD patients are more impaired when they have to rely upon internal control for the regulation of shifting attention than when external cues are available.

Aged↗
PubMed1989

Haloperidol and cognitive shifting.

In this study haloperidol appeared to affect the performance on a selected category of cognitive tasks considered to represent shifting aptitude. A pretest--post-test design was used with two groups of subjects: 17 patients suffering from idiopathic spasmodic torticollis, and 17 controls who were matched for age and intelligence. The results are discussed in relation to previous findings on haloperidol and cognition, shifting disorder in Parkinson's disease and changes in behavioural organization found in animals with an experimentally induced dopaminergic hypoactivity.

Attention↗
PubMed1984

Cognitive and motor shifting aptitude disorder in Parkinson's disease.

Eighteen patients suffering from Parkinson's disease and nineteen control subjects, who were matched for age and intelligence, were compared in tests measuring "shifting aptitude" at cognitive and motor levels (word production, sorting blocks or animals, and finger pushing sequences). It was found that Parkinson patients produced fewer different names of animals and professions in one minute than control subjects, needed more trials for detecting a shift in a sorting criterion, and produced fewer finger responses in a change of pushing sequence than control subjects. These results are interpreted as reflecting a central programming deficit that manifests itself in verbal, figural and motor modalities, that is, a diminished "shifting aptitude" characteristic of patients with dysfunctioning basal ganglia. The results are discussed in relation to changes of behaviour organisations in animals with dysfunctioning basal ganglia.

Aged↗
PubMed1981

Structure and function in neurobiology: a conceptual framework and the localization of functions.

A framework of concepts on structure and function of the nervous system is presented, in which we attempt to formulate the intended meanings of some ambiguous statements on structure and function in neurobiology in a set of strictly defined concepts. Function. The word "function" as generally used has different meanings. Two meanings of the question "What is the function of B?" are particularly relevant for this subject: (1) "What does B do?" and (2) "Why did B evolve?" It is shown that question 1 must be answered before question 2. Function of brain region S. The question "What does brain region S do?" has a meaning identical to the question "What is the relation between inputs and outputs of S, at specified conditions of S?" The answer to this question is the I/O-function. The I/)-function can be described at different levels, for instance at the molecular or cellular level. When neuroscientists ask "What is the function of brain region S?", the intended meaning appears to be either "What is the extra-CNS I/O-function of S?," or "Why did S evolve?" The "extra-CNS I/O-function of CNS subsystem S" is "the I/O-function of S in which input and output elements are outside the CNS". In many cases, neuroscientists want to know the "behavioral I/O-function of CNS subsystem S," i.e., the "I/O-function of S in which input and output elements are outside the organism"; they want to know "what is represented by the inputs of S outside the organism, and what are the effects of the outputs of S outside the organism." Loosely speaking, when a neuroscientist wants to know "the function of brain region S," he wants to know "the meaning of its neural messages, and their behavioral effects." Some examples of generally accepted behavioral I/O-functions of clearly sensory and motor parts of the CNS are presented. Localization of function. The following conclusions are drawn for "localization of function F." (1) "Function F" must be specified as "I/O-function F' " referring to input and output elements outside the CNS. (2) "Localization of I/O-function F' " is a kind of shorthand for "identification of the neural activity representing the states of these input and output elements." (3) If neurons exist whose activity only (or mainly) represents this input ("pontifical cells"), and/or only (or mainly) generates this output ("command neurons") (or, in other words, whose behavioral I/O-function is F'), it might be said metaphorically that "function F is localized in these neurons." In most cases, the existence of such neurons is still on open question.

Animals↗