This study compares the validity and usability of smartphone software for home monitoring of symptoms and signs in Parkinson's disease as compared to the current clinical gold standard - the Unified Parkinsons Disease Rating Scale.

Parkinson's Disease (PD) is a neurodegenerative condition, which when treated can result in fluctuating motor activity - sometimes too much movement, sometimes too little.

A series of tests, run on a smartphone, will be used to evaluate the motor signs of Parkinson's and related to a clinical evaluation based on the Unified Parkinson's Disease Rating Scale. 60 participants will be recruited.

Inclusion Criteria:

1. Diagnosed with probable idiopathic Parkinson's Disease according to Brain Bank criteria (Gibb and Lees, 1988).
2. Over 18 years old.
3. Achieve >20/30 on the Montreal Cognitive Assessment (MOCA).
4. They must have been on the current Parkinson's Disease medication schedule for at least a week and have no plans to change this during the period of testing.
5. They must have the capacity to consent to take part in the study.
6. They must be able to understand English to the level of being able to operate the phone software, follow its instructions and be able to answer the study questions.

Exclusion Criteria:

1. Acute medical illness.
2. Any other co-morbidity that in the opinion of the Investigator may preclude their participation in the study.
3. Unable to consent to the study.