Ms. Pitts described findings from two groups of 20 cognitively intact PD patients studied for relationships between dysphagia and cough. They were divided into two groups: one with symptoms of dysphagia, and the other with no dysphagia symptoms but who had slightly dysfunctional cough. They all had mild to moderate PD.
Explore This IssueJune 2008
Patients were asked to swallow large 30-cc boluses. Such a large bolus was used in order to challenge the patient’s ability to swallow.
If you challenge the system, we begin to see the impairment. If we let them act within their normal range, then they still can look pretty normal-especially in this population with milder disease, Ms. Pitts said.
Penetration-aspiration scores were measured, using a scale of 1 to 8. This describes the depth at which the material enters the airway. The level of the laryngeal vestibule would be a 3, for instance, whereas getting below the level of the vocal fold with no response is an 8. Video fluoroscein exams were judged by two people.
All three phases of cough were measured. Cough volume acceleration was also measured, which we think is an indirect measure of how effective a cough is, she said. Measurements of air displacement were performed with pneumotacograph. Cough data were compared to normative data in the medical literature, as well as between the two groups.
The penetration-aspiration group was found to have reduced expiratory peak flow. Compared with normal rates, our penetration-aspiration group are falling outside the normal range, she said. The non-penetration-aspiration group still fell within normal range for duration and peak expiratory flow.
Overall, patients in the penetration-aspiration group had a general slowing down of cough. They seem to have difficulty moving and switching from the inspiratory phase to the expiratory phase …we’re seeing really long compression times. The pattern that’s emerging is that it takes longer for them to get through the entire action, Ms. Pitts said.
Expiratory Muscle Strength Training
The question then arose as to whether expiratory muscle strength training would help make cough more effective in PD patients. Researchers developed the device that is now known as EMST. The device has a spring-loaded valve that can be set at different pressure levels, and the maximum expiratory pressure patients produce can be measured. Patients train at 75% of their maximum.
Sent home with the device, PD patients were told to do five sets of five breaths, five days a week, for a total of four weeks. Ms. Pitts presented data from 10 patients who had dysphagia and who penetrated or aspirated into the laryngeal vestibule during swallow tasks.