Clinical Review

The Nonmotor Symptoms of Parkinson’s Disease: Update on Diagnosis and Treatment

Journal of Clinical Outcomes Management. 2014 February;21(2)

 

References

Interestingly, many studies are now investigating the relationship between presence of RBD and later onset of neurodegenerative disorders. Multiple studies have shown that 40% to 65% of patients diagnosed with idiopathic RBD later develop an alpha-synucleinopathy, which includes PD, dementia with Lewy bodies, or multiple system atrophy within 10 years [92,95]. Prior studies report that as many as 90% of patients with idiopathic RBD develop neurodegenerative synucleinopathy when followed over 14 years [96]. Idiopathic RBD is currently being investigated as a potential clinical marker of pre-symptomatic PD in a multicenter observational study. If RBD is an early marker for neurodegenerative disease, it may be used to identify patients for neuroprotective trials as treatments are developed.

Treatment Options

Low-dose clonazepam (0.25–1 mg) is the mainstay of therapy, especially for patients that injure themselves or bed partners [97]; however, the use of benzodiazepines is historical and there remain no randomized controlled double-blind studies to evaluate the efficacy of clonazepam. Use of clonazepam may be limited by daytime sedation, confusion, or psychomotor agitation [31,97,98]. Melatonin (doses between 3–12 mg at bedtime) has also demonstrated benefit in RBD in a double-blind, placebo-controlled trial and in a small case series, with fewer side effects and no addiction potential as compared to clonazepam [99,100]. Case reports also support the use of several other effective medications, including cholinesterase inhibitors (rivastigmine and donepezil) and dopaminergic agents (pramipexole and levodopa) [15,20].

Restless Leg Syndrome and Periodic Limb Movements in Sleep

Epidemiology

Restless leg syndrome (RLS) and periodic limb movements in sleep (PLMS) cause disruptions of sleep and have an important impact on quality of sleep in PD patients. RLS is described as a strong urge to move the legs, accompanied by an uncomfortable sensation that is exacerbated at rest and relieved by movement. RLS is more frequently diagnosed in patients with PD, though prevalence reports vary widely [15]. Secondary causes for RLS should be investigated including iron deficiency, uremia and polyneuropathy. Several case reports demonstrate onset or worsening of RLS with use of antidepressants [101, 102] or antipsychotics like risperidone, aripiprazole, and quetiapine [103,104].

PLMS occurs in approximately 80% to 90% of patients with RLS, though may be present independently, and when seen on polysomnography is supportive of RLS [105]. PLMS is characterized by repetitive dorsiflexion of the foot, extension of the great toe, and may be accompanied by flexion of the knee and hip. The prevalence of PLMS in PD is approximately 60% and correlates with severity of PD motor features [106].

Treatment Options

Treatment of RLS should be initiated with nonpharmacologic therapies including good sleep hygiene, exercise, leg massage, and heat or ice packs [105,107]. Dopamine (DA) agonists are the primary treatment for RLS; however, even modest adjustments in levodopa can be helpful. One drawback to levodopa therapy is augmentation (a worsening or reappearance of symptoms) when serum levels fall due to the short half-life of levodopa [107,108]. DA agonists are less likely to cause augmentation. Both pramipexole and ropinirole have been extensively investigated in controlled, randomized, double-blind studies with benefits in 70% to 90% of patients with RLS and PLMS; however, there is a risk of developing compulsive behaviors [109–112]. Another option for PD patients is rotigotine, which has demonstrated improvement of RLS symptoms in a randomized, double-blind, placebo-controlled trial and has the added benefit that it may also help with motor symptoms [113,114].

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