Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.
Mohn Medical Imaging and Visualization Centre, Haukeland University Hospital, Bergen, Norway.
PLoS One. 2019 Sep 3;14(9):e0221752. doi: 10.1371/journal.pone.0221752. eCollection 2019.
Previous research has demonstrated that people with Parkinson's disease (PD) have difficulties with the perceptual discrimination of rhythms, relative to healthy controls. It is not however clear if this applies only to simpler rhythms (a so called "beat-based" deficit), or if it is a more generalized deficit that also applies to more complex rhythms. Further insight into how people with PD process and perceive rhythm can refine our understanding of the well known problems of temporal processing in the disease. In this study, we wanted to move beyond simple/complex-dichotomy in previous studies, and further investigate the effect of tempo on the perception of musical rhythms. To this end, we constructed ten musical rhythms with a varied degree of complexity across three different tempi. Nineteen people with PD and 19 healthy controls part-took in an internet based listening survey and rated 10 different musical rhythms for complexity and likeability. In what we believe is the first study to do so, we asked for the participants subjective ratings of individual rhythms and not their capacity to directly compare or discriminate between them. We found an overall between-group difference in complexity judgments that was modulated by tempo, but not level of complexity. People with PD rated all rhythms as more complex across tempi, with significant group differences in complexity ratings at 120 and 150bpm, but not at 90bpm. Our analysis found a uniform elevated baseline for complexity judgments in the PD-group, and a strong association between the two groups' rank-ordering the rhythms for complexity. This indicates a preserved ability to discriminate between relative levels of complexity. Finally, the two groups did not significantly differ in their subjective scoring of likeability, demonstrating a dissimilarity between judgment of complexity and judgment of likeability between the two groups. This indicates different cognitive operations for the two types of judgment, and we speculate that Parkinson's disease affects judgment of complexity but not judgment of likeability.
先前的研究表明，与健康对照组相比，帕金森病（PD）患者在节奏的感知辨别方面存在困难。然而，目前尚不清楚这种情况是否仅适用于更简单的节奏（所谓的“基于节拍”的缺陷），或者是否是一种更普遍的缺陷，也适用于更复杂的节奏。进一步深入了解 PD 患者如何处理和感知节奏，可以深化我们对该疾病中众所周知的时间处理问题的理解。在这项研究中，我们希望超越先前研究中的简单/复杂二分法，并进一步研究节奏速度对音乐节奏感知的影响。为此，我们构建了十个具有不同复杂程度的音乐节奏，分为三个不同的节奏速度。19 名 PD 患者和 19 名健康对照组通过互联网参与了一项听力调查，并对 10 种不同的音乐节奏进行了复杂性和喜好度的评分。我们相信这是首次这样做的研究，我们要求参与者对单个节奏进行主观评分，而不是直接对它们进行比较或辨别能力的评估。我们发现，在复杂性判断方面存在整体的组间差异，且该差异受节奏速度调制，但不受复杂程度的影响。PD 患者在所有节奏速度下都将所有节奏评为更复杂，在 120 和 150bpm 时存在显著的组间差异，但在 90bpm 时则没有。我们的分析发现，PD 组的复杂性判断存在一个统一的升高基线，并且两组对节奏的复杂性进行排序的相关性很强。这表明 PD 患者在相对复杂程度的辨别方面具有保留的能力。最后，两组在喜好度的主观评分上没有显著差异，表明两组之间在复杂性判断和喜好度判断上存在差异。这表明这两种判断涉及不同的认知操作，我们推测帕金森病会影响复杂性判断，但不会影响喜好度判断。
