Distler Michael, Schlachetzki Johannes Cm, Kohl Zacharias, Winkler Jürgen, Schenk Thomas
Department of Neurology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany.
Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany.
Neuropsychologia. 2016 Jun;86:38-44. doi: 10.1016/j.neuropsychologia.2016.04.012. Epub 2016 Apr 15.
Slowness of movement, called bradykinesia is the cardinal symptom of Parkinson's disease. Under distinct but not yet well-defined circumstances, patients with Parkinson's disease are able to overcome bradykinesia. One common hypothesis for this phenomenon termed paradoxical kinesia in Parkinson's disease postulates that the presentation of external sensory triggers is pivotal to elicit significant increase of motor velocity. In the present study, we examined an alternative hypothesis, namely that an internal cue in the absence of sensory cues are linked to paradoxical kinesia. To test this alternative hypothesis, patients with Parkinson's disease and healthy age-matched controls (n=9 per group) performed two movement tasks. In the stationary-object prehension task, subjects had to pick up a stationary target object. For the escaping-object task, the participants had to pick up the target object before it moved out of reach. The time available to reach for the object was adjusted individually to ensure comparable difficulty across participants. Reaction time, movement duration, and maximum velocity were assessed for both movement tasks. In Parkinson's disease patients and healthy controls, anticipation of the imminent movement of a target object significantly decreased reaction time, movement duration, and increased maximum movement velocity. The increase of maximum movement velocity in the escape-condition was significantly more pronounced for Parkinson's disease patients as compared to healthy controls. We provide evidence that internal cues such as temporal constraints are sufficient to diminish the cardinal clinical symptom of bradykinesia in Parkinson's disease. Our results suggest that expectations rather than sensory cues are critical for the emergence of paradoxical kinesia and we discuss the implications of our findings for an account of paradoxical kinesia.
运动迟缓，即所谓的运动徐缓，是帕金森病的主要症状。在特定但尚未明确界定的情况下，帕金森病患者能够克服运动迟缓。对于帕金森病中这种被称为矛盾运动的现象，一种常见的假设认为，外部感觉触发因素的呈现对于引发运动速度的显著增加至关重要。在本研究中，我们检验了另一种假设，即不存在感觉线索时的内部线索与矛盾运动有关。为了验证这一替代假设，帕金森病患者和年龄匹配的健康对照者（每组n = 9）进行了两项运动任务。在静止物体抓取任务中，受试者必须拿起一个静止的目标物体。对于逃逸物体任务，参与者必须在目标物体移出可及范围之前拿起它。为确保参与者之间难度相当，可用于伸手拿取物体的时间进行了个体化调整。对两项运动任务都评估了反应时间、运动持续时间和最大速度。在帕金森病患者和健康对照者中，预期目标物体即将运动显著缩短了反应时间和运动持续时间，并提高了最大运动速度。与健康对照者相比，帕金森病患者在逃逸条件下最大运动速度的增加更为明显。我们提供的证据表明，诸如时间限制等内部线索足以减轻帕金森病中运动迟缓这一主要临床症状。我们的结果表明，期望而非感觉线索对于矛盾运动的出现至关重要，并且我们讨论了我们的发现对矛盾运动解释的影响。
