Diagnostic work up when suspecting early onset Parkinson disease (EOPD). Recommendations from the MDS EOPD study group

Introduction: Early onset Parkinson's disease (EOPD) has been defined as PD with onset of motor symptoms after age 21 but before age 50. While diagnostic criteria are clear, data suggest that clinicians are still uncomfortable making the diagnosis, resulting in multiple investigations and delays in diagnosis and initiation of treatment. Methods: Following the Delphi process, the 15 members of the steering committee of the EOPD study group of the International Parkinson Disease and Movement Disorder Society (MDS) designed and completed a 10 binary or multiple-choice questions survey then met to establish recommendations regarding which investigations are needed for the diagnosis of EOPD. Results: The average age of the 15 respondents (5 females) was 49 years, with 18.2 years average experience in the management of EOPD (range 9–30 years). All geographic sections of the MDS were represented to account for variability of practice. The committee discussed the role of brain MRI, Dopamine transporter (DaT) SPECT scan, laboratory investigation, and genetic testing when suspecting EOPD. Conclusion: If EOPD is suspected on history and examination without any additional findings concerning for secondary or genetic parkinsonism, we recommend limiting investigations to brain MRI and laboratory investigation for Wilson's disease. This may expedite diagnosis and starting the appropriate treatment. Genetic testing is not necessary for diagnosis but can be useful to identify new genetic etiologies which could plausibly be used for trial inclusion.