SAN JUAN, P.R. – Treating the manifestations of sleep disorders requires a broad understanding of patients' circumstances, Donald Bliwise, Ph.D., said at the annual meeting of the American Association for Geriatric Psychiatry.
For example, both restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) become more prevalent as patients age, said Dr. Bliwise, professor of neurology at Emory University in Atlanta. “RLS is really a symptom,” he said. PLMD is a polysomnographic finding, and the two often overlap. However, neither is necessary nor sufficient to make the diagnosis of the other. In order for RLS to be diagnosed, communication between the patient and the physician is critical. A diagnosis of PLMD often must be preceded by a report from the patient's bed partner of excessive movement.
RLS is characterized by uncomfortable leg sensations. These sensations are worse in the evening and at night, and worse with inactivity. Leg movement relieves the discomfort. “If someone has constant pain and discomfort, it's probably less likely to be RLS,” said Dr. Bliwise, director of the program in sleep, aging, and chronobiology at Emory. RLS is associated more with motor hyperactivity.
PLMD is characterized by stereotypic, repetitive movements of the legs–and less often the arms–during sleep or inactivity; these movements are detected by EEG in the sleep laboratory. Movements occur every 20–40 seconds and usually occur in groups of four. These movements may be associated with arousals from sleep. Sometimes the movements occur in only one limb or may switch back and forth between limbs.
Dr. Bliwise also said RLS and PLMD are very dependent on ferritin levels. “So one of the first things we do, especially with our geriatric patients, is check ferritin-iron levels,” Dr. Bliwise said. If the patient has low levels, he or she is put on iron supplementation.
RLS and PLMD are also associated with chronic renal failure, neuropathies, myelopathies, radiculopathies, pregnancy, and folate and vitamin B12 deficiencies. Some medications can worsen RLS and PLMD; in particular, tricyclic antidepressants and selective serotonin reuptake inhibitors can aggravate these two conditions. Dopamine agonists are often used off label for these two conditions. Ropinirole (Requip) is indicated for the treatment of RLS.
Sleep disorders are also common in synucleinopathies and Alzheimer's disease but have different clinical presentations. “With these two broad classes of neurodegenerative conditions, you really have two kinds of clinical pictures as far as sleep disturbance is concerned,” Dr. Bliwise said.
Parkinson's disease (PD) and PD-like conditions (synucleinopathies) are often characterized by the suspension of normal REM atonia. “Often with these patients, you get a history of combativeness,” Dr. Bliwise said. They awaken from sleep often with confusion and may believe that they are being attacked, which leads to combative behavior. These patients are also sleepy during the day. These signs may even predate PD-like conditions by as much as 20 years. In terms of treating both Parkinson's disease and PD-like conditions, clonazepam, dopamine agonists, and even melatonin have been used off label with some success.
In contrast, “in Alzheimer's disease, what we typically see is agitation in the late afternoon or early evening hours–the so-called sundown syndrome,” Dr. Bliwise said. Studies have shown that this phenomenon is associated with changes in circadian rhythms. Other studies have shown that there is a profound loss of cells in the suprachiasmatic nucleus in patients with Alzheimer's disease.
Keep in mind that cholinesterase inhibitors used in treating Alzheimer's are associated with disturbed sleep. Studies suggest that these drugs may increase both REM sleep and insomnia. Atypical antipsychotics, which are sometimes used off label to treat Alzheimer's disease, are associated with somnolence. “Basically, the adverse effect of somnolence is what we're banking on when we try to use these [atypical antipsychotics] to try to treat disturbed sleep in these patients,” Dr. Bliwise said.
Finally, it is important not to overlook nocturia in patients with disordered sleep, Dr. Bliwise said. In fact, a direct association exists between the number of times a person wakes during the night to urinate, the person's age, and complaints of sleep. “It's amazing how often this is overlooked as a cause of disordered sleep,” Dr. Bliwise said. Nocturia has been associated with sleep apnea, another factor in disordered sleep.