Interoception in Parkinson's disease: A narrative review and framework for translational research

Parkinson's disease (PD) is the second most common, and the fastest growing, neurodegenerative disease worldwide. Non-motor manifestations, particularly autonomic nervous system dysfunction, are common throughout the disease course, in some cases preceding motor symptom onset by years, and are often more disabling and harder to treat than motor symptoms and contribute significantly to disability. An understudied consequence of autonomic and visceral dysfunction in PD is interoception, the neural processing of internal organ system signals. Interoceptive processes form a foundational body-brain interface, mediating basic homeostatic reflexes and complex physiologic and behavioral adaptive responses to internal perturbations. Emerging evidence exists that interoception is impaired in some individuals with PD, potentially explaining why those who have objective evidence of autonomic dysfunction do not always report typical symptoms. Failure to recognize these impairments may lead to missed opportunities for early intervention, particularly in addressing 'silent' autonomic disturbances (e.g., orthostatic hypotension leading to sudden falls, dysphagia leading to aspiration pneumonia). In this narrative review, we synthesize current findings on the neuroanatomical networks underlying interoception, examine clinical manifestations of interoceptive dysfunction across multiple organ systems in PD, and identify key gaps in knowledge. We propose a translational research framework to enhance early detection, symptom management, and intervention strategies for PD. This framework integrates cognitive, mood, and autonomic dysfunctions with clinical factors (disease stage, duration, motor subtype, levodopa status) to understand interoceptive dysfunction within a translational model. This approach highlights novel opportunities for personalized care and improved therapeutic interventions in PD.