Respiratory Load Magnitude Estimation in PD
Condition: Parkinson's Disease; Aging
MeSH terms: Parkinson Disease
Study type: Observational

Summary: 
      The purpose of this study is to determine whether people with Parkinson's disease (PD)
      experience reduced perception of respiratory resistive loads versus healthy adults in the
      same age group. Further, the study will determine whether people with PD and trouble
      swallowing experience even more reduction of their perception of a respiratory resistive
      load.
    

Detailed description: 
      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).
    

Intervention name(s): Respiratory resistive load on inhalation; Fluoroscopic swallowing evaluation
Intervention type(s): Other; Other
Intervention description(s): The participant will be seated in a chair, and will be instructed to "relax and breathe" through a facemask. Five respiratory resistive loads (5-40 cmH2O resistive pressure) will be applied between 3-5 times during inhalation. Following each loaded breath, participants will rate the perceived difficulty of breathing in.; Participants with PD only will receive a swallowing evaluation as part of their routine clinical care. 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. Results are reviewed by the treatment speech-language pathologist, and 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.
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        This study will include 2 participant groups: those with Parkinson's disease, and healthy
        age- matched control participants. We will recruit 40 healthy older adults and 40
        individuals with PD to participate. We will recruit all participants with PD from those
        referred for swallowing evaluation by the speech-language pathology service at the
        University of Florida (UF) Center for Movement Disorders and Neurorestoration (CMDNR).
        Healthy participants will be recruited via the UF Institutional Review Board's (IRBs)
        Healthstreet program, and local/campus advertisements.
      
Keywords: respiratory sensation; somatosensation; resistive load; magnitude estimation