NEW YORK (Reuters Health) - A new practice parameter from the American Academy of Neurology calls for doctors to identify and treat nonmotor symptoms in patients with Parkinson's disease (PD).
Nonmotor symptoms - autonomic dysfunction, sleep disorders, psychological and cognitive problems, and sensory abnormalities - are major, often unrecognized causes of morbidity in PD. In 2006 and 2008, the Academy issued guidelines pertaining to cognitive and mood dysfunction in PD as well as treatment of sialorrhea with botulinum toxin.
To evaluate treatment options for other nonmotor PD symptoms, Dr. Theresa A. Zesiewicz from the University of South Florida in Tampa and associates searched MEDLINE, EMBASE, and the Science Citation Index and identified 46 controlled trials published between 1966 and 2008.
Most trials supporting specific treatments provided only level C evidence, the researchers report in the March 16th issue of Neurology. The only recommendation backed by level B evidence was the use of levodopa/carbidopa (Atamet, Sinemet) to treat periodic limb movements of sleep.
One trial evaluated the efficacy of sildenafil (Viagra) in 12 patients with erectile dysfunction. Sildenafil was more effective than placebo at enabling men to achieve and maintain an erection, with minimal changes in blood pressure. The authors advise a complete medical evaluation to rule out other treatable causes of erectile dysfunction.
For excessive daytime sleepiness, modafinil (Provigil) might be useful. However, modafinil might improve patients' perception of wakefulness without improving objective measures of sleepiness, creating a potential safety hazard if patients engage in activities such as driving.
Methylphenidate (Ritalin) might help patients with fatigue, but the authors warn of the potential for abuse. They note that PD patients "have a risk for dopamine dysregulation syndrome and impulse control disorders that share many clinical and functional imaging features with addiction."
Isosmotic macrogol (polyethylene glycol or Miralax) possibly improved constipation in one study. Increased water and dietary fiber intake have also been helpful.
However, for many conditions considered - orthostatic hypotension, urinary incontinence, insomnia, rapid eye movement sleep behavior disorder, and anxiety -- the authors found insufficient evidence to support or refute treatments.
Dr. Zesiewicz and associates advise physicians to diagnose nonmotor symptoms in PD using tools such as the NMS Quest study questionnaire and the updated version of the Unified Parkinson's Disease Rating Scale.
Concluding, the investigators write, "There are few dedicated controlled trials of drugs to treat nonmotor symptoms in PD. Such trials are urgently required."
However, co-author Dr. William J. Weiner commented in an interview with Reuters Health, "The truth is that when we do these very formal surveys of the literature looking for evidence in a rigorous manner, it's quite common that we can't find much evidence." That doesn't mean that many of the measures that physicians commonly use to treat nonmotor PD symptoms aren't helpful, he added.
Dr. Weiner, from the University of Maryland Medical Center, Baltimore, continued, "It's also helpful for patients to know that they don't have another disease (when they develop these symptoms), so they don't have to see a cardiologist or a GI specialist or a urologist; that in fact it's part of what is going on with them."
Reference:
Neurology 2010;74:924-931.
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