Probiotic Treatment for Depression and Associated Mood Disorders in Parkinson's Disease

Inventory of Depressive Symptomatology - Clinician-Rated (IDS-C)

The Inventory for Depressive Symptomatology is a measure of depressive signs and symptoms administered by a trained clinician. The score range is 0-84 points, with a higher score indicating greater levels of depressive symptomatology.

Beck Depression Inventory, 2nd Edition (BDI-II)

The Beck Depression Inventory is a self-reported 21-question multiple-choice self-report inventory on a scale from 0-63. A higher score indicates greater characteristic attitudes and symptoms of depression. BDI-II is also used as a screening item for mild to moderate depression for this study.

Quick Inventory of Depressive Symptomatology - Self Report (QIDS-SR)

QIDS-SR is a 16-item, self-administered questionnaire used to assess the severity of depressive symptoms over the past 7 days, based on DSM-IV criteria. QIDS-SR is a shortened version of IDS-C, but QIDS-SR is self-rated (filled in the form of a questionnaire) and IDS-C is clinician-rated (administered as a clinical assessment), so using both assessments allows us to incorporate both self-rated and clinician-rated measures. The score range is 0-27 points, with a higher score indicating greater levels of depressive symptomatology.

Fatigue Severity Scale (FSS)

The Fatigue Severity Scale is a self-reported 9-item scale which measures the severity of fatigue and its effect on a person's activities and lifestyle in patients with a variety of disorders on a scale from 1 (strongly disagree) to 7 (strongly agree). The minimum score is 9 and the maximum score is 63. A higher score indicates greater fatigue severity.

Montreal Cognitive Assessment (MoCA)

The Montreal Cognitive Assessment test is a one-page, 30-point assessment administered by trained individuals that is used for detecting mild cognitive impairment and dementia. Score may range from 0-30 points and a lower score may indicate greater cognitive impairment.

Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS)

The Movement Disorder Society Unified Parkinson's Disease Rating Scale is a clinical assessment of motor and non-motor symptoms in individuals with Parkinson's Disease (PD). It consists of four subscales. Subscales 1, 3, and 4 are administered by a trained individual and subscale 2 is self-reported. Each item is rated from 0 to 4. The total score can range from 0-199, with a higher score indicating greater impairment in PD.

Parkinson's Anxiety Scale (PAS)

The Parkinson's Anxiety Scale is a 12-point observer or patient-rated scale that has three subscales: persistent anxiety, episodic anxiety, and avoidance behaviour. It is rated using a Likert scale (0-4). Possible scores range from 0-48, with a higher score indicating greater severity of anxiety symptoms.