Parkinson disease: Not just a movement disorder
ABSTRACTNonmotor symptoms are common in Parkinson disease and can significantly worsen the health and quality of life of the patient and family members. These symptoms can be broadly categorized as sensory, autonomic, cognitive-behavioral, and sleep-related. Clinicians can improve the care of these patients by recognizing and addressing these problems.
KEY POINTS
- Nonmotor symptoms can be due to the disease itself, to its treatment, or to on-off fluctuations in motor status as doses of medication wear off.
- Impaired sense of smell, depression, anxiety, fatigue, and constipation can precede the motor symptoms of Parkinson disease and may be symptoms of the disease itself.
- Orthostatic hypotension, sedation, psychosis, confusion, and impulsiveness may be adverse effects of medical therapy or may worsen with it.
- Depression occurs in up to 50% of patients with Parkinson disease, although it may be difficult to recognize because many of its physical features can also be manifestations of Parkinson disease itself.
SLEEP DISORDERS
Excessive daytime sleepiness
Fatigue and hypersomnolence often impair quality of life.61 Daytime hypersomnolence is often multifactorial: it can be caused by the disease itself,62 by dopaminergic therapy,63,64 by a comorbid illness, or by nighttime sleep problems.
Sudden and uncontrollable episodes of sleep are an extreme form of hypersomnolence and are worrisome, especially with activities such as driving.65 Greater sleepiness (measured by the Epworth Sleepiness Scale), longer duration of Parkinson disease, and use of dopaminergic agonists increase the risk of such attacks.66 In general, very few patients experience such attacks without warning signs of sedation.
Treatment must include a comprehensive evaluation of current medications, the effect of dopaminergic agents (especially agonists), and nighttime factors that influence sleep (some of which are described below). Modafinil (Provigil), effective in narcolepsy, helped in some studies67 but not in others68; it could be tried in moderate to severe cases of excessive daytime sleepiness.
Sleep apnea contributes to daytime hypersomnolence. An evaluation for sleep apnea should be considered even in patients who are not overweight, as some evidence suggests that this disorder is common in Parkinson disease and correlates with disease severity.69
Insomnia
Sleep is impaired in up to 74% of Parkinson patients.70,71 A sleep study may show a low total sleep time, many awakenings, a short rapid-eye movement (REM) latency, and short slow-wave sleep (stages III and IV); the patient experiences the problem as light sleep with frequent awakenings.72 A variety of problems related to Parkinson disease can directly affect sleep patterns: eg, pain, stiffness, tremor, problems turning over in bed, dystonia, dementia, nocturia,73 depression, and anxiety.74
Restless legs syndrome
Restless legs syndrome is an uncomfortable, sometimes painful feeling in the legs or other body parts during rest (especially at night) that improves with movement.75 It may be more common in patients with Parkinson disease than in the general population76,77 and can precede the diagnosis of Parkinson disease.78
Iron supplementation with ferrous sulfate can help if iron deficiency (ferritin < 50 μg/L or iron saturation < 16%) is present but is ineffective in its absence. Levodopa and the dopaminergic agonists ropinirole (Requip)70 and pramipexole (Mirapex)80 are effective Parkinson disease treatments that also treat restless legs syndrome. In addition, opioids, clonazepam, and gabapentin (Gabarone) may help.81
Vivid dreams
Parkinson patients often describe very vivid, intense, frightening, and unpleasant dreams,73 which may be a precursor to psychosis.82
REM sleep behavior disorder is characterized by sustained phasic muscle activity in place of normal atonia during REM or dream sleep. The patient's bed partner may describe him or her behaving in an aggressive way as if acting out his or her dreams, ie, hitting, yelling, or kicking. Upon awakening, the patient's recall of the dream content is consistent with the nocturnal behavior.
REM sleep behavior disorder may actually precede the motor symptoms of Parkinson disease,83,84 and as many as 20% of patents with REM sleep behavior disorder eventually develop Parkinson disease.85 The possible link between the two disorders is strengthened by a case report describing a patient with REM sleep behavior disorder, no signs of Parkinson disease on examination, but brain pathology similar to that found in Parkinson disease.86
Clonazepam is an effective treatment for REM sleep behavior disorder and should be considered if sleep is disrupted or patient safety becomes a concern.87
