Puce Luca, Marinelli Lucio, Currà Antonio, Mori Laura, Schenone Cristina, Cotellessa Filippo, Tatarelli Antonella, Pucci Daniele, Bragazzi Nicola Luigi, Trompetto Carlo
Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Italy.
IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
PLoS One. 2024 Dec 18;19(12):e0315274. doi: 10.1371/journal.pone.0315274. eCollection 2024.
Paratonia is an involuntary muscle activity that occurs during passive joint mobilization and is common in people with dementia. It includes oppositional paratonia, in which muscle activity resists passive movement, and facilitatory paratonia, in which it assists movement. This phenomenon reflects a defect in motor response inhibition. In a recently published paper, we demonstrated that paratonia can be detected using surface electromyography (EMG) not only in patients with dementia but also in healthy individuals, the majority of whom do not exhibit clinically observable paratonia. This finding suggests that EMG-assessed paratonia may provide a novel approach to studying motor response inhibition in healthy subjects. The present study investigates this possibility for the first time. We recruited 120 healthy subjects under the age of 30, divided equally into three groups: sedentary, amateur, and professional athletes with low, moderate, and high levels of physical activity, respectively. Paratonia was assessed in the triceps and biceps brachii muscles during passive forearm movements performed manually. The results indicate that paratonia is more pronounced during fast and continuous passive movements, with facilitatory paratonia being more prevalent than oppositional paratonia. It is also more pronounced in the biceps than in the triceps. These findings, which mirror those previously observed in patients with dementia, suggest a similarity between paratonia in healthy subjects and those with cognitive impairment, supporting the hypothesis that paratonia in healthy individuals represents a form of impaired motor response inhibition. Furthermore, the comparison between groups showed that paratonia decreased with increasing physical activity, being least evident in athletes, more noticeable in amateurs, and most pronounced in sedentary individuals. This pattern confirms a key feature of motor response inhibition that has been shown in studies using traditional methods. Overall, our findings suggest that EMG-assessed paratonia provides a new method for studying motor response inhibition in healthy individuals.
折刀样张力是一种在被动关节活动时出现的不自主肌肉活动，在痴呆患者中很常见。它包括对抗性折刀样张力，即肌肉活动抵抗被动运动；以及辅助性折刀样张力，即肌肉活动辅助运动。这种现象反映了运动反应抑制方面的缺陷。在最近发表的一篇论文中，我们证明不仅可以使用表面肌电图（EMG）在痴呆患者中检测到折刀样张力，在健康个体中也能检测到，其中大多数人并没有临床上可观察到的折刀样张力。这一发现表明，通过肌电图评估的折刀样张力可能为研究健康受试者的运动反应抑制提供一种新方法。本研究首次探讨了这种可能性。我们招募了120名30岁以下的健康受试者，平均分为三组：久坐不动者、业余运动员和专业运动员，他们的身体活动水平分别为低、中、高。在手动进行的被动前臂运动过程中，对肱三头肌和肱二头肌的折刀样张力进行了评估。结果表明，在快速连续的被动运动中折刀样张力更为明显，辅助性折刀样张力比对抗性折刀样张力更为普遍。在肱二头肌中也比在肱三头肌中更明显。这些与之前在痴呆患者中观察到的结果相似的发现，表明健康受试者和认知障碍患者的折刀样张力存在相似性，支持了健康个体中的折刀样张力代表一种运动反应抑制受损形式的假设。此外，组间比较表明，折刀样张力随着身体活动水平的增加而降低，在运动员中最不明显，在业余运动员中更明显，在久坐不动者中最明显。这种模式证实了使用传统方法的研究所显示的运动反应抑制的一个关键特征。总体而言，我们的研究结果表明，通过肌电图评估的折刀样张力为研究健康个体的运动反应抑制提供了一种新方法。
