Weight Loss in Parkinson's Disease and Role of Small Bowel Bacterial Overgrowth

Hypothesis: Small bowel bacterial overgrowth is an important contributor to the development
of weight loss in individuals with Parkinson's disease.

Specific aims: 1) To determine the prevalence of SBBO in consecutive patients seen in a
Parkinson's disease specialty clinic, and 2) To evaluate the effect of SBBO treatment in PD
patients with weight loss.

Study design: Prospective, observational case-control study with open-label therapeutic
component. Cases will be defined as those PD patients who've experienced significant weight
loss while Controls will be defined as those PD patients who have not experienced
significant weight loss.

Part 1:

Consecutive patients seen in the Parkinson's disease clinic at MCA will be approached to
participate. After the determination of their eligibility and appropriate signed informed
consent, all PD patients (i.e., both Case and Control groups) will undergo the following:

1. Assessment of demographic features, weight history and PD history

2. PD and other medications

3. Determination of PD severity using the Unified Parkinson's Disease rating scale

4. Evaluation of gastrointestinal symptoms (GISSI and modified GISSI)

5. Determination of usual calorie and nutrient intake (Brief Block Food Frequency
Questionnaire)

6. Paffenbarger physical activity questionnaire

7. Quality of life (SF12 and PD-specific)

8. HAD survey

9. Glucose hydrogen breath test (SBBO test)

10. Qualitative assessments of smell and taste

All questionnaires will be completed during the 2 hour breath test.

Part 2:

All individuals in the weight loss group (i.e., only the Case group) will be offered
open-label treatment with the poorly absorbed antibiotic, rifaximin, 550 mg PO BID for 14
days. Treatment will not depend upon the results of the bacterial overgrowth breath test.
Thus, both normal and abnormal breath test subjects will receive antibiotic treatment. The
patient will be contacted by phone 1 month after treatment at which time the presence of GI
symptoms will be determined and inquiry made about any adverse effects related to rifaximin
use. GI symptoms, quality of life, weight measurement and breath testing will be repeated at
a 3 month study visit.

Inclusion criteria: Parkinson's Disease

Exclusion Criteria:

1. Wheelchair-bound, akinetic individuals

2. Tube-fed individuals

3. Presence of dementia

4. Unwilling or unable to complete the tests

5. Allergic or intolerant to rifaximin

6. Presence of chronic upper or lower gastrointestinal disorders that have symptoms that
may be confused with SBBO (e.g., irritable bowel syndrome, inflammatory bowel
disease, celiac disease, functional dyspepsia, gastroparesis, and chronic
pancreatitis)

7. Presence of prior surgery on the gastrointestinal tract except cholecystectomy,
appendectomy or herniorrhaphy

8. Presence of severe concomitant acute or chronic medical condition that may interfere
with the completion or interpretation of the test results

9. Women of childbearing potential. Given the age of patients with Parkinson's disease,
we do not anticipate this being a large population.

10. Use of antibiotics within 1 month of breath testing