Fontana G A, Pantaleo T, Lavorini F, Benvenuti F, Gangemi S
Dipartimento di Fisiopatologia Clinica, Sezione di Fisiopatologia Respiratoria, Università di Firenze, and U. O. di Geriatria, Ospedale I.N.R.C.A., "I Fraticini," Florence, Italy.
Am J Respir Crit Care Med. 1998 Aug;158(2):458-64. doi: 10.1164/ajrccm.158.2.9705094.
The high incidence of serious chest infections in patients with Parkinson's disease is unexplained, but an impairment in cough reflex may have a role. Maximal voluntary cough (MVC) and reflex cough (RC) to inhalation of ultrasonically nebulized distilled water were analyzed in patients with Parkinson's disease and age-matched control subjects by monitoring the integrated electromyographic activity (IEMG) of abdominal muscles. The peak amplitude of IEMG activity (IEMGP) was expressed as a fraction of the highest IEMGP value observed during MVC corrected to account for possible losses in abdominal muscle force due to reduced central muscle activation. Cough intensity was indexed in terms of both the IEMGP and the ratio of IEMGP to the duration of the expiratory ramp (TEC), i.e., the rate of rise of IEMG activity. Cough threshold was slightly higher in patients than in control subjects, but the difference failed to reach statistical significance. Compared with control subjects, patients displayed a lower IEMGP during maximal expiratory pressure maneuvers (PEmax), MVC, and RC (p always < 0.01); TEC during RC was longer (p < 0.01) than in controls. Consequently, the rate of rise of IEMG activity during cough was always lower in patients (p < 0. 01), especially during RC. Finally, PEmax, and both the peak and rate of rise of IEMG activity during RC were inversely related to the level of clinical disability (Spearman rank correlation coefficient, rs = -0.88, -0.86, and -0.85, respectively, p always < 0.01). The results indicate that the central neural mechanisms subserving the recruitment of motor units and/or the increase in their frequency of discharge during voluntary and, even more markedly, RC are impaired in patients with Parkinson's disease.
帕金森病患者严重胸部感染的高发病率原因不明，但咳嗽反射受损可能起到一定作用。通过监测腹部肌肉的综合肌电图活动（IEMG），对帕金森病患者和年龄匹配的对照受试者吸入超声雾化蒸馏水后的最大自主咳嗽（MVC）和反射性咳嗽（RC）进行了分析。IEMG活动的峰值幅度（IEMGP）表示为在MVC期间观察到的最高IEMGP值的一部分，并进行校正以考虑由于中枢肌肉激活减少导致的腹部肌肉力量可能损失。咳嗽强度通过IEMGP以及IEMGP与呼气斜坡持续时间（TEC）的比值来衡量，即IEMG活动的上升速率。患者的咳嗽阈值略高于对照受试者，但差异未达到统计学显著性。与对照受试者相比，患者在最大呼气压力动作（PEmax）、MVC和RC期间的IEMGP较低（p均<0.01）；RC期间的TEC比对照组长（p<0.01）。因此，患者咳嗽期间IEMG活动的上升速率始终较低（p<0.01），尤其是在RC期间。最后，PEmax以及RC期间IEMG活动的峰值和上升速率与临床残疾程度呈负相关（斯皮尔曼等级相关系数，rs分别为-0.88、-0.86和-0.85，p均<0.01）。结果表明，帕金森病患者在自愿咳嗽，尤其是反射性咳嗽期间，负责运动单位募集和/或其放电频率增加的中枢神经机制受损。
