Respiratory Load Magnitude Estimation in PD

Experimental design and procedures: This prospective experimental study will be completed in
one study visit taking between 1 and 3 hours. Verbal and written informed consent will be
obtained by qualified members of the investigative team. Following informed consent, all
participants will complete a health history questionnaire to assess inclusion/exclusion
criteria. For patients with PD the consenting investigator will review the electronic
medical record to ensure inclusion/exclusion criteria are met.

The experimental protocol will consist of 1.) Baseline pulmonary function measures, 2.)
Baseline measures of depression and apathy, 3.) Presentation of resistive inspiratory loads
via respiratory equipment, and 4.) Rating the perceived magnitude of respiratory sensations
as measured on a modified Borg scale (ranging from 6 - no breathing difficulty - to 20 -
maximal difficulty). For patients with PD only, the investigators will also review results
of the rehabilitation barium swallow study performed as part of their standard clinical
care.

Baseline Pulmonary function measures: The forced expired volume in the first second (FEV1)
of a forced vital capacity (FVC) exhalation will be measured for each participant. Maximum
inspiratory pressure (PiMax) will be measured with a manometer. The PiMax test will be
repeated until 3 measurements within 10% variation are obtained, with at least 1 minute rest
between trials.

Baseline depression and apathy: There is a significant impact for emotion on respiratory
perceptual ratings. As such, we will measure baseline depression and apathy scores using 2
validated scales, the Beck Depression Index (BDI) and Marin Apathy Index (MAI). These are
not outcome measures, but will be used to determine exclusion criteria.

Should depression (17 or greater on BDI) be detected in a participant, that participant will
be provided with contact information for the University of Florida (UF) psychiatry and
psychology clinic and encouraged to seek further evaluation. In the case severe depression
is detected (31 or greater on BDI) the participant will not continue with the study, and
will be provided with contact information for the UF psychiatry and psychology clinic and
encouraged to seek further evaluation.

Inspiratory resistive load presentation:

The participant will be seated in a chair, separated from the investigator and experimental
apparatus. The participant will be instructed to "relax and breathe" through a facemask
connected to a non-rebreathing valve in line with a differential pressure transducer. The
inspiratory port of the valve will be connected to the resistive loading manifold. The
manifold consists of 5 differential resistors ranging from 5 - 40 centimeters/water (cmH2O)
of resistive pressure, separated by stoppered ports, as well as a no load condition. The
load is applied by removing the stop for an entire inspiratory breath, and then replacing
the port to continue resting tidal breathing. The pressure transducer will provide measures
of mouth pressure and airflow, which will be digitized and recorded to a desk top computer
using LabChart software. Following each loaded breath, the participant will provide an
estimate of the perceived difficulty of breathing using a modified Borg scale.

Participants will be familiarized with the loads in a practice session prior to initiating
the experimental protocol. During the experimental session, participants will listen to
music of their choice in order to mask experimental sounds. The resistive loads will be
applied in a randomized block design, with each loaded breath separated by at least three
unloaded breaths. Two blocks will be completed with each load presented between 3 and 5
times within each block. Therefore, there will be a total of between 15 and 25 loaded
breaths (3-5 loads x 5 presentations) per block. Participants will be instructed that when
they see a small light flash briefly on the table in front of them (which they will be
familiarized with prior to beginning the experiment) a resistive load will be applied to the
next breath. Following the loaded breath, the participant will be asked to estimate the
perceived difficulty of breathing on the Borg scale.

Rehabilitation barium swallow study: Participants with PD who are referred for a
rehabilitation barium swallowing evaluation will be recruited for this study. Therefore, the
swallowing evaluation is part of the normal clinical care of the patients and may vary based
on the clinical necessity as judged by the treating speech-language pathologist. Generally,
the standard clinical evaluation protocol consists of multiple swallows of thin liquid
barium, pudding-thick barium, and a cracker or cookie coated with barium. For the purposes
of this study, the researchers will review the most recently recorded swallow study and
identify the worst observed penetration-aspiration (PA) score (ranging from 1-8, where 1 is
no penetration or aspiration, and 8 is silent aspiration). The PA score will be recorded in
order to determine whether the participant has trouble swallowing (scores of 3-8) or not
(scores of 1 and 2).

Inclusion Criteria:

- Between the ages of 45 and 85

- Ability to provide informed consent

- Patient group: Diagnosis of PD, Hoehn and Yahr stages II - IV, by a UF Movement
Disorders fellowship trained neurologist having completed a clinical assessment of
each participant's PD severity and arriving at the diagnosis of PD by applying strict
UF brain bank criteria.

- Healthy older adults: History of PD, or any other neurologic or neurodegenerative
disease including stroke.

Exclusion Criteria:

- History of head and neck cancer, and radiation treatment to the head or neck

- History of breathing disorders or diseases (e.g. chronic obstructive pulmonary
disease (COPD), asthma, lung cancer)

- History of smoking in the past 5 years, or for more than 5 years at any one time

- Severe cognitive deficits including dementia.

- Difficulty complying with protocol due to severe neuropsychological disorder (i.e.,
severe depression: 31 or greater on the BDI)