Dresang Haley C, Williamson Rand, Kim Hana, Hillis Argye E, Buxbaum Laurel J
Moss Rehabilitation Research Institute, 50 Township Line Rd, Elkins Park, PA 19027.
University of Pennsylvania, Perelman School of Medicine, Department of Neurology, 3400 Spruce St, Philadelphia, PA 19104.
Aphasiology. 2024;38(11):1853-1868. doi: 10.1080/02687038.2024.2326449. Epub 2024 Mar 12.
Primary progressive aphasia (PPA) is a neurodegenerative syndrome characterized by progressive language deficits. The main variants of PPA -semantic (svPPA), logopenic (lvPPA), and nonfluent (nfvPPA)- can be challenging to distinguish. Limb apraxia often co-occurs with PPA, but it is unclear whether PPA variants are associated with different gesture deficits. Prior evidence from stroke indicates that temporal lobe lesions are associated with reduced benefit from meaning in gesture performance. Temporal lesions are also associated with greater deficits in hand postures compared to arm kinematics in gesture imitation.
We tested the hypothesis that svPPA, who primarily exhibit temporal lobe atrophy, would differentially show this pattern. In addition, we predicted that as a group, individuals with PPA would more accurately produce meaningful than meaningless gestures and kinematic components than hand postures, as found in neurotypical adults and individuals with stroke.
METHODS & PROCEDURES: Participants with PPA completed meaningful and meaningless gesture imitation tasks. Performance was scored for hand posture and arm kinematic components. Bayesian mixed-effect models examined trial-level gesture imitation accuracy, while controlling for dementia severity and random effects of subjects and items. Fixed effects included an interaction between PPA variant, task condition/meaning, and gesture component.
OUTCOMES & RESULTS: We found a critical interaction between PPA variant, meaning, and gesture component. In particular, unlike lvPPA and nfvPPA, svPPA subjects' hand postures failed to benefit from gesture meaning. This preliminary research extends prior findings on the role of the temporal lobe in action representations associated with manipulable objects, and is among the first to demonstrate distinct gesture imitation patterns between PPA variants.
Characterizing gesture deficits in PPA may help inform diagnostics, compensatory communication strategies, and models of praxis.
原发性进行性失语（PPA）是一种以进行性语言缺陷为特征的神经退行性综合征。PPA的主要变体——语义性（svPPA）、音韵性（lvPPA）和非流利性（nfvPPA）——可能难以区分。肢体失用症常与PPA同时出现，但尚不清楚PPA变体是否与不同的手势缺陷相关。先前中风的证据表明，颞叶病变与手势表现中从意义中获得的益处减少有关。与手势模仿中的手臂运动学相比，颞叶病变还与手部姿势的更大缺陷有关。
我们检验了以下假设，即主要表现为颞叶萎缩的svPPA会有不同的这种模式表现。此外，我们预测，与典型成年人和中风患者一样，PPA患者作为一个群体，在做出有意义的手势和运动成分时会比无意义的手势和手部姿势更准确。
PPA患者完成有意义和无意义的手势模仿任务。对手部姿势和手臂运动成分的表现进行评分。贝叶斯混合效应模型在控制痴呆严重程度以及受试者和项目的随机效应的同时，检验试验水平的手势模仿准确性。固定效应包括PPA变体、任务条件/意义和手势成分之间的相互作用。
我们发现PPA变体、意义和手势成分之间存在关键的相互作用。特别是，与lvPPA和nfvPPA不同，svPPA受试者的手部姿势未能从手势意义中受益。这项初步研究扩展了先前关于颞叶在与可操作物体相关的动作表征中的作用的研究结果，并且是最早证明PPA变体之间存在不同手势模仿模式的研究之一。
描述PPA中的手势缺陷可能有助于为诊断、代偿性沟通策略和实践模型提供信息。
