Abstract
A comprehensive, patient-centered conceptual model of early Parkinson's is lacking and is greatly needed. A systematic review and meta-synthesis of qualitative and quantitative research was conducted by a multi-stakeholder taskforce using JBI Mixed Methods Review criteria and GRADE-CERQual standards for assessment of evidence. Over 340 symptoms and impacts were identified across ten symptom domains (Movement, Cognitive, Psychiatric, Sleep, Sensory, Speech, Digestive, Urinary, Sexual, Autonomic) and two impact domains (Physical and Psychosocial functioning). A wide range of motor and non-motor symptoms were present in early disease, with strongest support for tremor, dexterity, gait, stiffness, slow movements, cognitive, mood, and sleep alterations, urinary dysfunction, constipation, pain, and fatigue. These affected mobility, self-concept, coping, effort of living, interactions and important activities, with evidence of many understudied concepts. This model offers the most comprehensive catalogue of symptoms and impacts in Parkinson's to date and will support clinical practice and endpoint selection for therapeutic trials.