How do frontotemporal dementias such as Pick’s disease and corticobasal degeneration affect sleep? Learn about these conditions, including their most common symptoms, and how dementia that affects the frontal and temporal lobes of the brain impacts sleep.
What Is Frontotemporal Dementia?
Dementia includes various disorders that progressively affect the brain and may impact memory, attention, personality, language, problem solving, and daily function. Within this broad category, there are conditions that affect specific areas of the brain and lead to specific dysfunction. One of these more specific types is frontotemporal dementia (FTD), a disorder that affects the frontal and temporal lobes of the brain (located at the front and lower sides of the brain). It affects 5 to 15 percent of people with dementia.
Frontotemporal dementia includes two distinct conditions: Pick’s disease and corticobasal degeneration. The former is characterized by specific abnormal findings called Pick bodies, found within neurons of the brain that contain an abnormal amount or type of protein called tau. There are genes that seem to contribute to the occurrence of this disease, but the exact cause remains unknown. Pick’s disease is a rare condition that often occurs in people who are 40 to 60 years old.
In contrast, corticobasal degeneration (CBD) is characterized by the gradual loss of neurons in the cerebral cortex and basal ganglia, two areas of the brain that are critical to thinking and movement. This atrophy may affect one side of the body at first, but as the disease progresses, both sides of the body may become involved. CBD may start around the age of 60.
What Are the Symptoms of Frontotemporal Dementia?
The area of the brain affected in frontotemporal dementia leads to a specific set of symptoms. With Pick’s disease, early personality and behavioral changes may occur. This may be manifest as difficulty in social settings with odd, compulsive, or inappropriate behavior. In contrast, Alzheimer’s disease is often characterized by memory loss as the main symptom. People with Pick’s disease may have abrupt mood changes or seem uncaring (apathetic), and there may be problems related to speech (called aphasia) and impaired thinking. In time, weakness or discoordination may develop. As a rule, these symptoms will progressively worsen.
Corticobasal degeneration has additional symptoms due to the effects on the basal ganglia. This can cause symptoms similar to Parkinson’s disease, including rigidity, slow movements, and imbalance. People with CBD will also develop apraxia, which is the inability to perform a purposeful movement even though the physical strength and coordination is present. As an example, someone with CBD may be unable to mimic the movements of brushing teeth, smoking a cigarette, combing hair, or eating soup from a spoon. These difficulties eventually make it impossible to walk. Speech may become halting, and difficulty swallowing may also occur.
Frontotemporal Dementia and the Effects on Sleep
The sleep of people with frontotemporal dementia can change, and in fact, the pattern of sleep and wakefulness is altered. The normal circadian rhythm becomes highly fragmented, with a mixture of the two occurring both day and night. This seems to extend beyond the changes that can occur when living in an assisted living facility like a nursing home. Affected people more commonly have an advanced sleep phase, falling asleep and waking earlier than normal.
When observed with an electroencephalogram (EEG), the rhythm of the brain waves is abnormal: it's slower during wakefulness. Nevertheless, it may be normal in up to one third of people, so it's not a perfect test to diagnose the condition.
Other sleep disorders can occur in frontotemporal dementia for the same reasons that they occur in the general population, including sleep apnea. These may require further evaluation and an appropriate level of treatment, depending on the underlying impairment from the dementia.
Treatment and Prognosis in Frontotemporal Dementia
There are no specific treatments that can slow or reverse the course of these dementias. Therapy, including the use of medications, may be targeted to alleviate specific symptoms, but unfortunately, these may be resistant to intervention. Supportive care is imperative, including providing a safe environment with the necessary level of assistance.
The prognosis in frontotemporal dementia is generally poor, with a course that progresses and worsens — and disability is also a common part of the diseases. Pick’s disease will lead to death within 2 to 10 years, typically from infection (such as pneumonia or urinary tract infection), or another complication of the severe impairment. Corticobasal degeneration follows a similar time course, progressing over 6 to 8 years and leading to death in similar ways.
It's important that caregivers and loved ones of people with frontotemporal dementia maintain a network of support and obtain relief as needed. Disrupted sleep can be a small component in the context of the other difficulties, but disruption to sleep patterns still takes a toll on the affected person and his or her caregivers. So treating sleep disruption may benefit from intervention and ease the caregiving burden.
If you find you need additional assistance in managing this condition, you may benefit from consultation with a neurologist, who can help coordinate the care and provide referral to resources in your community.
Kryger, MH et al. "Principles and Practice of Sleep Medicine." Elsevier, 5th edition, p. 1042.
"Pick’s disease." PubMed Health. Accessed: January 30, 2013.
"NINDS Corticobasal Degeneration Information Page." National Institute of Neurological Disorders and Stroke. Accessed: January 30, 2013.