The Movement Disorder Society (MDS) clinical diagnostic criteria were created to standardise the diagnosis of PD, making it both accurate and reproducible.1 The MDS criteria provide expert guidance for clinicians, particularly those with less experience in the field of PD, by setting out clear and unambiguous clinical diagnostic criteria.1
The MDS method is similar to the UK Parkinson Society Brain Bank Clinical Criteria in that it first requires a diagnosis of parkinsonism, which can then be either supported or excluded by additional criteria.1 As with the UK Parkinson Society Brain Bank Clinical Criteria, there is a category of absolute exclusion criteria, such as an absence of a response to levodopa therapy, supranuclear gaze palsy or cerebellar signs.1 There are also additional ‘red flag’ criteria which, if present, require counterbalancing by additional supportive evidence of PD.1
A diagnosis of ‘clinically-established’ PD requires the absence of any absolute exclusion criteria, along with at least two supportive criteria, and no red flags.1 A diagnosis of ‘clinically-probable’ PD requires the absence of any absolute exclusion criteria along with sufficiently counter-balanced supportive criteria.1 Up to two ‘red flags’ are allowed, but should be offset by an equal number of supportive criteria.1