Eshghi Marziye, Perry Bridget J, Richburg Brian, Ventresca Hayden M, Pomahac Bohdan, Green Jordan R
Speech and Feeding Disorders Lab, MGH Institute of Health Profession, Boston, MA, United States.
Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
Front Neurol. 2021 Jan 6;11:593153. doi: 10.3389/fneur.2020.593153. eCollection 2020.
Despite signs of facial nerve recovery within a few months following face transplantation, speech deficits persist for years. Behavioral speech modifications (e.g., slower-than-normal speaking rate and increased loudness) have shown promising potential to enhance speech intelligibility in populations with dysarthric speech. However, such evidence-based practice approach is lacking in clinical management of speech in individuals with facial transplantation. Because facial transplantation involves complex craniofacial reconstruction and facial nerve coaptation, it is unknown to what extent individuals with face transplant are capable of adapting their motor system to task-specific articulatory demands. The purpose of this study was to identify the underlying articulatory mechanisms employed by individuals with face transplantation in response to speech modification cues at early and late stages of neuromotor recovery. In addition, we aimed to identify speech modifications that conferred improved speech clarity. Participants were seven individuals who underwent full or partial facial vascularized composite allografts that included lips and muscles of facial animation and were in early (2 months) or late (42 months) stages of recovery. Participants produced repetitions of the sentence "Buy Bobby a puppy" in normal, fast, loud, and slow speech modifications. Articulatory movement traces were recorded using a 3D optical motion capture system. Kinematic measures of average speed (mm/s) and range of movement (mm) were extracted from the lower lip (± jaw) marker. Two speech language pathologists rated speech clarity for each speaker using a visual analog scale (VAS) approach. Results demonstrated that facial motor capacity increased from early to late stages of recovery. While individuals in the early group exhibited restricted capabilities to adjust their motor system based on the articulatory demands of each speech modification, individuals in the late group demonstrated faster speed and larger-than-normal range of movement for loud speech, and slower speed and larger-than-normal range of movement for slow speech. In addition, subjects in both groups showed overreliance on jaw rather than lip articulatory function across all speech modifications, perhaps as a compensatory strategy to optimize articulatory stability and maximize speech function. Finally, improved speech clarity was associated with loud speech in both stages of recovery.
尽管面部移植后几个月内有面神经恢复的迹象，但言语缺陷会持续数年。行为性言语调整（如，比正常语速慢和音量增大）已显示出在改善构音障碍人群言语清晰度方面具有可观的潜力。然而，这种基于证据的实践方法在面部移植个体的言语临床管理中尚不存在。由于面部移植涉及复杂的颅面重建和面神经接合，目前尚不清楚面部移植个体在何种程度上能够使其运动系统适应特定任务的发音需求。本研究的目的是确定面部移植个体在神经运动恢复的早期和晚期阶段，对言语调整线索做出反应时所采用的潜在发音机制。此外，我们旨在确定能提高言语清晰度的言语调整方式。研究参与者为7名接受了包括嘴唇和面部表情肌的全脸或部分面部血管化复合组织异体移植的个体，处于恢复的早期（约2个月）或晚期（约42个月）阶段。参与者以正常、快速、大声和慢速的言语调整方式重复句子“给博比买只小狗”。使用3D光学动作捕捉系统记录发音运动轨迹。从下唇（±下颌）标记点提取平均速度（毫米/秒）和运动范围（毫米）的运动学指标。两名言语语言病理学家使用视觉模拟量表（VAS）方法对每位参与者的言语清晰度进行评分。结果表明，面部运动能力从恢复早期到晚期有所提高。早期组个体根据每种言语调整的发音需求调整其运动系统的能力受限，而晚期组个体在大声言语时表现出更快的速度和比正常更大的运动范围，在慢速言语时表现出较慢的速度和比正常更大的运动范围。此外，两组受试者在所有言语调整方式中都表现出过度依赖下颌而非嘴唇的发音功能，这可能是一种优化发音稳定性和最大化言语功能的补偿策略。最后，在恢复的两个阶段，言语清晰度的提高都与大声言语有关。
