Defining 'OFF' time in device-aided therapy criteria for Parkinson's disease: gaps and opportunities

Evaluating individuals with Parkinson's to determine if they have progressed to the advanced stage and may be suitable for transitioning from intermittent oral medications to continuous, device-aided therapy (DAT) involves considering multiple clinical factors. A key parameter in this assessment, and an indicator of a declining response to oral medication, is overall daily OFF time and the occurrence of unpredictable OFF episodes. OFF-periods are, however, complex and experienced differently by individual patients, so assessment of duration alone may not provide an accurate picture of the patient's lived experience and the challenges they face, information which can be helpful in deciding appropriate management. A range of useful screening tools are available to assist clinicians in determining if a patient has advanced disease and may be suitable for DAT, but these do not always capture the aspects of OFF periods that are the most important, or the most bothersome, to patients. To improve recognition, enhance patient-clinician communication, and achieve effective, personalized management of OFF periods, we propose expanding these tools to consider additional dimensions in three specific areas. First, incorporate patient insights into the personal and functional impact, including the severity of OFF periods, effects on daily activities, and the types and timing (daytime or nighttime) of episodes. Second, include specialist advice from clinicians to characterise the nature of these symptoms and determine suitable therapies. Finally, support this with objective information from PD diaries or technology-based monitoring.