Unmet needs in the pharmacological management of motor symptoms in Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder clinically defined by the presence of cardinal motor features like bradykinesia, rigidity and resting tremor. The mainstay of PD treatment is pharmacological dopamine substitution and responsiveness of motor symptoms to levodopa is a supporting diagnostic feature of this illness. Although the armentarium of drugs to treat the motor symptoms of PD and their efficacy on a variety of motor problems are overall impressive, significant unmet needs persist, particularly in the advanced stages of PD. These include situations of poorly responsive tremor, motor complications associated with sustained levodopa exposure, disorders of gait and balance as well as impairments of posture, speech and swallowing. This review provides an overview of available treatment strategies for these areas of unmet need and emerging therapies under development. Future perspectives include novel pharmacological targets, new modes of drug delivery, combination therapies and the integration of real-time monitoring and wearable technologies to tailor treatments.