Noël L. W. Keijsers

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We examined the role of gaze in a task where subjects had to reproduce the position of a remembered visual target with the tip of the index finger, referred to as pointing. Subjects were tested in 3 visual feedback conditions: complete darkness (dark), complete darkness with visual feedback of the finger position (finger), and with vision of a well-defined(More)
We developed an objective and automatic procedure to assess the severity of levodopa-induced dyskinesia (LID) in patients with Parkinson's disease during daily life activities. Thirteen patients were continuously monitored in a home-like situation for a period of approximately 2.5 hours. During this time period, the patients performed approximately 35(More)
Indirect evidence suggests that patients with Parkinson's disease (PD) have deficits not only in motor performance, but also in the processing of sensory information. We investigated the role of sensory information processing in PD patients with a broad range of disease severities and in a group of age-matched controls. Subjects were tested in two(More)
We developed an algorithm that distinguishes between on and off states in patients with Parkinson's disease during daily life activities. Twenty-three patients were monitored continuously in a home-like situation for approximately 3 hours while they carried out normal daily-life activities. Behavior and comments of patients during the experiment were used(More)
We have investigated pointing movements toward remembered targets after an intervening self-generated body movement. We tested to what extent visual information about the environment or finger position is used in updating target position relative to the body after a step and whether gaze plays a role in the accuracy of the pointing movement. Subjects were(More)
Dynamic plantar pressure images are routinely used in clinical gait assessment, and peak pressure, mean pressure, and pressure-time integral are the most frequently used parameters to summarize these images. Many studies report only one parameter, but other studies report all three. The interdependency of these variables has not been explicitly studied(More)
Levodopa-induced dyskinesias (LID) in Parkinson's disease (PD) have remained a clinical challenge. We evaluated the feasibility of neural networks to detect LID and to quantify their severity in 16 patients with PD at rest and during various activities of daily living. The movements of the patients were measured using four pairs of accelerometers mounted on(More)
Plantar pressure measurement provides important information about the structure and function of the foot and is a helpful tool to evaluate patients with foot complaints. In general, average and maximum plantar pressure of 6-11 areas under the foot are used to compare groups of subjects. However, masking the foot means a loss of important information about(More)
It is well known that long-term use of levodopa by patients with Parkinson's disease causes dyskinesia. Several methods have been proposed for the automatic, unsupervised detection and classification of levodopa induced dyskinesia. Recently, we have demonstrated that neural networks are highly successful to detect dyskinesia and to distinguish dyskinesia(More)