What's in a name? reframing advanced Parkinson's disease as a multidimensional state

"What's in a name?" is more than a literary question for advanced Parkinson's disease (APD). Although APD is widely used in clinical practice, what constitutes "advanced" remains poorly defined and inconsistently applied. Existing definitions have often anchored APD to motor complications, treatment complexity, or eligibility for device-aided therapies (DATs). These approaches are useful for referral and treatment planning, but they risk mistaking a treatment phenotype for the whole disease state. They also fail to capture the broader burden of progression, including non-motor symptoms, cognitive decline, functional dependence, psychosocial consequences, caregiver burden, frailty, and biological heterogeneity. We argue that APD is best understood as a multidimensional state reflecting cumulative neurodegeneration and its lived, functional, and therapeutic consequences, rather than a single stage, motor phenotype, or treatment milestone. This narrative review reframes APD through five interconnected axes: clinical symptom burden; perceived disease impact; functional consequences and participation restriction; therapeutic complexity, refractoriness, and treatment-related complications; and markers associated with disease progression. We propose that APD is a multidimensional clinical state that emerges as PD progresses, when cumulative burden across these five domains exceeds the capacity of patients and caregivers to compensate, adapt, and maintain independence, resulting in progressive disability and reduced quality of life. This framework distinguishes DAT-eligible PD, late-stage PD, and overlapping intermediate phenotypes, while accommodating emerging markers without replacing clinical judgement. By making the name APD correspond more closely to clinical reality, this framework may support earlier recognition, appropriate referral, patient-centred therapeutic planning, and more consistent research stratification.