Stroke, Memory Loss, and Sleep: The Role of Vascular Dementia

Damage to the Brain via Strokes May Undermine Sleep Quality

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There is an important overlap between memory loss and risk factors for stroke that might suggest a condition called vascular dementia. What is vascular dementia? Learn about the symptoms and treatment of this condition and how it might affect sleep among those afflicted.

What Is Vascular Dementia?

Dementia refers to a disorder characterized by the chronic and progressive impairment of memory, loss of reasoning, and personality changes that result from various causes.

One of the potential causes of this perceived memory loss is the accumulation of numerous small strokes within the brain. A stroke is the sudden loss of blood flow to an area of the brain that may lead to symptoms of weakness, numbness, vision loss, and speech difficulty. Strokes may also impact cognitive function, affecting language, memory, and organization. Dementia may occur in about 25 to 33 percent of people following a stroke.

Vascular dementia is characterized by a subtle and progressive worsening of memory that occurs in a stepwise fashion due to strokes occurring within the brain. Deficits may begin suddenly and then remain stable during a plateau period before more insults to the brain occur. It can be difficult to distinguish from Alzheimer’s disease clinically, which occurs five times as often and is due to a different disease process. The conditions may overlap in some people.

Risk factors for vascular dementia are the same as those for stroke. These include:

  • Hypertension
  • High cholesterol (hyperlipidemia)
  • Cardiac disease
  • Diabetes
  • Male gender
  • Smoking
  • Alcohol use
  • Obstructive sleep apnea

These problems may lead to narrowing of the blood vessels supplying the brain, a process called atherosclerosis.

Decreased blood flow can lead to a sudden occlusion and damage to the area of the brain that was formerly supplied. The condition can be effectively diagnosed with magnetic resonance imaging (MRI) that will reveal these areas of damage.

Symptoms and Treatment of Vascular Dementia

Individuals with vascular dementia experience significant memory problems that impair their ability to live independently. Difficulties with organization and problem solving are common. Changes in mood such as depression, irritability, and apathy (lack of interest) frequently occur. Word recall is often impaired. Hallucinations or delusions occur more rarely, but these can be very upsetting. If strokes are impacting areas of the brain responsible for sensation, movement, balance, or vision, further symptoms may be present.

Evaluation by a neurologist is important to document the deficits and arrange additional testing, such as an MRI, as appropriate. Blood tests to assess B12, thyroid function, cholesterol levels, and glucose control are often done.

Beyond managing risk factors to reduce the occurrence of additional strokes, no further treatment is available for vascular dementia.

Vascular Dementia and Sleep

There is evidence that vascular dementia can lead to disruption of the normal cycles of sleep and wakefulness. This can lead to poor sleep quality. There does not seem to be a correlation between the degree of sleep disruption and the severity of intellectual deterioration. In other words, sleep may not be worse among those with more severe vascular dementia.

It is important to note that vascular dementia is more strongly associated with obstructive sleep apnea. This condition can contribute to mood and cognitive complaints, as well as excessive daytime sleepiness. Fortunately, if sleep apnea is present, effective therapy with continuous positive airway pressure (CPAP) may reduce the risk of further strokes. Depending on the degree of impairment, some people with dementia may be unable to comply with the treatment.

If you are concerned that you or a loved one may be suffering from vascular dementia, speak with your doctor and a sleep specialist about the required evaluation and potential ways to reduce the risk of further damage.

Sources:

Aharaon-Peretz, J et al. “Sleep-wake cycles in multi-infact dementia and dementia of the Alzheimer type.” Neurology. 1991;41:1616-1619.

Erkinjuntti, T et al. “Sleep apnea in multi-infarct dementia and Alzheimer’s disease.” Sleep. 1987;10:419-425.

Kryger, M.H. et al. “Principles and Practice of Sleep Medicine.” ExpertConsult, 5th edition, 2011, p. 1041.

Vascular Dementia.” Alzheimer's Association. Last accessed: February 28, 2015.

Vascular Dementia.” UCSF Memory and Aging Center. Last accessed: February 28, 2015.

What is stroke?National Stroke Association. Last accessed: February 28, 2015.

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