Department of Speech and Hearing Sciences, Portland State University (PSU), Portland, OR, USA.
Northwest Center for Voice and Swallowing, Department of Otolaryngology - Head and Neck Surgery, Oregon Health & Sciences University (OHSU), Portland, OR, USA.
Ann Otol Rhinol Laryngol. 2023 Mar;132(3):266-274. doi: 10.1177/00034894221089407. Epub 2022 Apr 17.
The impact of laryngeal dysfunction on airflow has not been well characterized in motor neuron disease (MND). This study aimed to detect and characterize extreme airflow oscillations informally observed during volitional cough and forced vital capacity (FVC) tasks in individuals with MND who demonstrated neurolaryngeal impairments including reduced speed and extent of vocal fold abduction compared to healthy controls during volitional cough expulsion. The extreme airflow oscillations in the MND group, when viewed as a flow-volume loop, appeared similar to the "sawtooth-sign." If the airflow oscillations are periodic in a range similar to phonation, they may reflect reduced laryngeal patency.
Volitional cough and FVC airflow data (3 trials each) from 12 participants with MND with bulbar/laryngeal involvement (3 F; ages 45-76) and 12 healthy controls (6 F; ages 41-68) were analyzed for periodicity. Percent and absolute durations of periodicity of the flow oscillations were calculated by an algorithm applied to the airflow signals. In addition, the frequency, magnitude, and kurtosis of the periodic airflow oscillations were described and compared between groups.
In both volitional cough and FVC trials, the percent of airflow periodicity during forced expiration was significantly higher ( = 3.54) in individuals with MND, adjusted for age and sex. Periodic airflow accounted for on average 28% of the total time in participants with MND and was within a frequency range similar to phonation. Magnitude of the airflow oscillations was also larger for participants with MND ( = 3.46), and kurtosis of airflow was smaller ( = -4.70) during forced expiration, indicating persistent airflow oscillations throughout exhalation.
The significantly larger-magnitude, lower-kurtosis, and more prominent presence of sawtooth-like airflow periodicity within a frequency range similar to phonation observed in individuals with MND with neurolaryngeal impairments suggests glottic airflow resistance during forced expiration.
喉功能障碍对气流的影响在运动神经元病（MND）中尚未得到很好的描述。本研究旨在检测和描述在 MND 患者中观察到的极端气流波动，这些患者在神经喉损伤方面表现出异常，包括与健康对照组相比，在自愿咳嗽呼气时声带外展的速度和幅度降低。在 MND 组中，这些极端气流波动在作为流量-容积环观察时，类似于“锯齿信号”。如果气流波动在类似于发声的范围内呈周期性，则可能反映了声门的通畅性降低。
分析了 12 名有球麻痹/喉受累的 MND 患者（3 名女性；年龄 45-76 岁）和 12 名健康对照者（6 名女性；年龄 41-68 岁）的自愿咳嗽和用力肺活量（FVC）气流数据（每项试验 3 次），以评估周期性。通过应用于气流信号的算法计算周期性气流波动的百分比和绝对持续时间。此外，还描述并比较了两组之间周期性气流波动的频率、幅度和峰度。
在自愿咳嗽和 FVC 试验中，MND 患者在强制呼气时的气流周期性百分比均显著升高（ = 3.54），校正了年龄和性别因素。周期性气流占 MND 患者总时间的平均 28%，且频率范围与发声相似。MND 患者的气流波动幅度也较大（ = 3.46），气流峰度较小（ = -4.70），表明在呼气过程中气流持续波动。
在神经喉损伤的 MND 患者中，观察到明显更大幅度、更低峰度、更突出的锯齿样气流周期性，其频率范围与发声相似，提示强制呼气时声门气流阻力增加。
