Non-motor Symptoms in Late-stage Parkinson’s Disease – Is Continuous Dopaminergic Stimulation Beneficial?
Non-motor Symptoms in Late-stage Parkinson’s Disease – Is Continuous Dopaminergic Stimulation Beneficial?
Parkinson’s disease (PD) was first described by James Parkinson in 1817 and remains one of the most important disabling illnesses of later life. Although the motor symptoms of the disease are easy to identify, the non-motor symptom (NMS) complex frequently goes unrecognised by healthcare professionals, as reported by Shulman and colleagues.1 This may be because physicians or nurses concentrate more on motor aspects, there is unawareness that NMS are related to PD or the symptoms are not declared to healthcare professionals.2 Recent work by the Parkinson’s Disease Non-motor Group (PD-NMG) has led to the validation of the first comprehensive clinic-based self-completed NMS questionnaire (NMSQuest, see Table 1),3 as well as a scale (the NMS scale) that allows easy identification of NMS by the physician.3,4
Patients often find the NMS of PD more disturbing than the motor symptoms. Indeed, NMS dominate the clinical picture of advanced PD and contribute to severe disability, impaired quality of life and shortened life expectancy. In contrast to the dopaminergic (motor) symptoms, for which treatment is available, NMS are often poorly recognised and inadequately treated. Some NMS – including depression, constipation, pain, genito-urinary problems and sleep disorders – can be improved with available treatments. Other NMS can be more refractory and need the introduction of novel nondopaminergic drugs. The development of treatments that can slow or prevent the progression of PD and its multicentric neurodegeneration provides the best hope of curing NMS.4
NMS correlate with advancing age and disease severity, although some NMS – such as olfactory problems, constipation, depression and rapid eye movement (REM) disorder – can occur early in the disease.2 The prevalence of NMS as a whole is inadequately documented because there are insufficient adequately powered community-based studies on prevalence, effect and treatment efficacy in relation to NMS; there is thus a need for large, well-designed prospective studies. The role and effect of the NMS complex during the disease course has been examined in a prospective study of patients with PD followed up for 15–18 years, which showed that non-levodopa-responsive NMS are the most disabling feature of the disease.5 A wide spectrum of NMS have been described in PD, as shown in Table 2.
- Shulman LM, Taback RL, Rabinstein AA, Weiner WJ, Nonrecognition of depression and other non-motor symptoms in Parkinson’s disease, Parkinsonism Relat Disord, 2002;8(3): 193–7.
- Chaudhuri KR, Yates L, Martinez-Martin P, The non-motor symptom complex of Parkinson’s disease: time for a comprehensive assessment, Curr Neurol Neurosci Rep, 2005;5:275–83.
- Chaudhuri KR, Martinez-Martin P, Schapira AHV, et al., An international multicentre pilot study of the first comprehensive self-completed non-motor symptoms questionnaire for Parkinson’s disease: the NMSQuest study, Mov Disord, 2006;21(7):916–23.
- Chaudhuri KR, Healy DG, Schapira AH, Non-motor symptoms of Parkinson’s disease: diagnosis and management, Lancet Neurol, 2006;5(3):235–45.
- Hely MA, Morris JGL, Reid WGJ, Trafficante R, Sydney multicenter study of Parkinson’s disease: non-L-doparesponsive problems dominate at 15 years, Mov Disord, 2005;20:190–99.
- Olanow W, Schapira AH, Rascol O, Continuous dopamine receptor stimulation in early Parkinson’s Disease, Trends Neurosci, 2000;23:S117–26.
- Stocchi F, Vacca L, Ruggieri S, et al., Intermittent vs. continuous levodopa administration in patients with advanced Parkinson’s disease; a clinical and pharmacokinetic study, Arch Neurol, 2005;62:905–10.
