RESUMEN
OBJECTIVES: To systematically investigate the ability of Parkinson's disease patients to discretely and dynamically scale the size of continuous movements and to assess the impact of movement size on outcome variability. METHODS: Ten patients with Parkinson's disease (mean age 72 years) were compared with 12 healthy elderly controls (mean age 70 years). The subjects wrote with a stylus on a graphics tablet. In experiment 1 they drew circles, matching the size of five target circles ranging in magnitude from a radius of 0.5 cm up to 2.5 cm. In experiment 2 they drew spirals with a radius of at least 2 cm. In both experiments the drawings were initially performed as accurately as possible then as fast and accurately as possible. RESULTS: In both experiments the patients and controls drew at a similar speed. The within trial variability of the pen trajectory was greater for patients than controls, and increased disproportionately with the size of the movement. When the emphasis was on size rather than variability (circles), the patients' drawing movements were the same size as controls. When the emphasis was on accuracy of pen trajectory (that is, minimum variability) rather than size (spirals), the patients' drawing movements were smaller than controls. CONCLUSIONS: The movements made by Parkinson's disease patients are hypometric partly as an adaptive strategy used to reduce movement variability. This strategy is used primarily when the requirement to make accurate movements outweighs the need to make large movements.
Asunto(s)
Actitud , Enfermedad de Parkinson , Trastornos Psicomotores/diagnóstico , Percepción del Tamaño , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad , Factores de TiempoRESUMEN
As the population continues to age, it has become increasingly important for clinicians to recognize the clinical characteristics of normal aging. Impaired mobility is one of the most frequent effects of normal aging, and this necessitates a specific understanding of the effects of normal aging on the motor system. This article reviews the physiological basis and clinical manifestations of normal aging as related to movement disorders. The impact of normal aging on major hypokinetic and hyperkinetic movement disorders is also discussed.