Vascular Cognitive Impairment

What is vascular cognitive impairment?

Vascular cognitive impairment (VCI) is if a form of dementia  that is believed to be caused by  damaged blood vessels in the brain, or cerebrovascular disease. When blood vessels lose their effectiveness, either because of age or other factors, such as high blood pressure or smoking, the brain can suffer reduction of blood flow.

A variety of definitions have been employed in the study of vascular cognitive impairment. Some have limited the term to include only cognitive impairment that is the result of ischemic stroke (a stroke caused by a blood clot). Others have broadened the term to include cognitive and behavioral changes that follow bleeding in the brain (intracerebral hemorrhage, subarachnoid hemorrhage or intraventricular hemorrhage). Some authors have sought a more restrictive definition, including only those patients who have microvascular ischemic stroke on MRI and excluding those with clinical strokes that occurred because of a blockage in a large artery.

Vascular cognitive impairment is widely viewed as the second leading cause of dementia (Alzheimer’s disease is the first). Vascular cognitive impairment is thought to be the dominant cause of dementia in up to 20 percent of people who develop dementia after age 65, and pathological changes suggest that VCI contributes to dementia in 33 to 40 percent of people over age 65. As with Alzheimer’s disease, the incidence (number of people who develop the disease at a given age) and prevalence (number of people who have the disease in a given age range) increase with age, although the rate of increase is not as fast as is seen in Alzheimer’s disease. The estimated prevalence of vascular cognitive impairment ranges from 1.2 to 4.2 percent of people over age 65.

What are the symptoms of vascular cognitive impairment?

Symptoms of vascular cognitive impairment (VCI) differ from the early symptoms of Alzheimer’s disease. Given the varied definitions of VCI, it is not surprising that clinical symptoms vary significantly in individual patients.
Vascular cognitive impairment is characterized most commonly by progressive accumulation of microvascular, or “subcortical,” strokes, which results in progressive neurologic dysfunction. Clinical symptoms include:

  • Memory deficits. Unlike the memory deficit in Alzheimer’s disease (in which the information was never encoded in the first place), memory impairment in VCI is most commonly a retrieval deficit. The memory impairment is typically regarded as milder than in Alzheimer’s and may be aided by “cues” or providing context, strategies that often fail in patients with Alzheimer’s disease.
  • Difficulties with executive function. Situations that require logical reasoning, “multitasking,” or organizing a set of steps to be completed in a particular order become more challenging.
  • Depression, apathy and personality changes, which are often more prominent early in the course of VCI.
  • “Pseudobulbar palsy,” which can appear in some patients and can include symptoms of emotional incontinence, paradoxical laughter.
  • Parkinsonism: slowness of movement (bradykinesia), increased rigidity in the arms and/or legs, and problems with walking (short stride length or a “magnetic” gait in which the feet seem glued to the floor).
  • Falls, which are more common early in VCI than early in Alzheimer’s disease.
  • Weakness or sensory changes affecting one side of the body.
  • Problems with speech (dysarthria), swallowing (dysphagia), double vision (diplopia), or other “focal” neurologic symptoms.
  • As alluded to above, in addition to these typical “subcortical-like” symptoms, some patients may have also experienced stroke involving a larger blood vessel and may have “cortical” signs including:
  • Aphasia (impairment of language)
  • Apraxia (loss of ability to perform learned motor movements
  • Visual impairment (loss of attention to part of a visual field, disturbances of visual integration)
  • Neglect – inattention to visual or sensory stimuli on one side (e.g., ignoring these things on the left side of the body)
  • Hemiparesis – weakness affecting one side of the body

Lastly, cognitive and behavioral changes may be part of the lasting neurologic deficits that follow subarachnoid hemorrhage or intraventricular hemorrhage. These cerebrovascular injuries often affect the brain in a more diffuse (widespread) manner, and the cognitive and behavioral changes can result in significant disability, even in the absence of observable motor changes.

Some individuals will exhibit changes in personality, becoming 1) more impatient, irritable or angry or 2) more sweet or docile.

What are risk factors for vascular cognitive impairment?

The risk factors for stroke should be familiar to you. These are diseases and conditions that your primary care physician has been screening for and discussing with you at each of your regular medical checkups. Addressing these conditions will reduce your risk of stroke and heart attack and will improve your overall medical health.
There are risks that you can reduce:

  • Diabetes is a major risk factor for stroke and for the microvascular changes often seen in association with vascular cognitive impairment. Improved glucose control can reduce your risk of stroke and cognitive impairment. Improved blood glucose control may also lessen your risk of developing Alzheimer’s disease.
  • Hypertension is a major risk factor for stroke and for the microvascular changes often seen in association with vascular cognitive impairment.
  • Elevation in the “bad” types of cholesterol (LDL and triglycerides) is associated with an increased risk of stroke. There is a poorer correlation with the microvascular changes discussed above.
  • If you smoke, quit now.
  • People with heart disease are at increased risk of stroke. This likely reflects the similarity in caliber (diameter) and composition of the coronary arteries in the heart and sveerla of the major blood vessels that deliver blood to the brain. Also, people with a history of heart disease may have decreased cardiac function, with decreased blood output form the heart (because the contractions are not as strong), which may increase the risk of developing a blood clot that is subsequently carried by the circulation to the brain.
  • Heart arrythmias (for example, atrial fibrillation) increase the risk of stroke.

There are also risk factors that you cannot change:

  • Getting older
  • Being male
  • Having a family history of heart disease and stroke
  • Being African-American

How is vascular cognitive impairment diagnosed?

Evaluation of a patient with cognitive symptoms always begins with a careful history, a physical examination and a thorough neurologic examination. Neuroimaging, typically a brain MRI or CT scan, can help corroborate the suspected presence of cerebrovascular disease by identifying areas of stroke or hemorrhage. This neuroimaging may also help to determine whether recent cerebrovascualr changes have occurred. If previous scans exist, comparison can help to determine whether progression of cerebrovascular changes has occurred.

The diagnosis of vascular dementia centers on the presence of cerebrovascular disease, the identification of cognitive impairment, and a likely causal relationship between the two. Thus, cognitive, behavioral and motor symptoms characteristic of vascular cognitive impairment and evidence of stroke on neuroimaging strongly suggest the diagnosis. Once other causes of cognitive impairment have been excluded, the diagnosis of probable vascular cognitive impairment can be made. If other causes of dementia are identified (for example, Alzheimer’s disease or Lewy body disease), a diagnosis of mixed dementia may be appropriate.

What types of further evaluation may be recommended?

Depending on the location, size and timing of cerebrovascular changes that have occurred, additional imaging studies of the arteries that supply blood to the brain can determine whether significant narrowing or blockage has increased a person’s risk for stroke.

In addition to brain imaging, evaluation of the heart’s function is also important. For some patients, echocardiography may be indicated to evaluate whether any structural abnormalities exist within the heart. This echocardiogram, typically performed by a cardiologist, may also help to measure the effectiveness of cardiac contractions at ejecting blood from the heart to the rest of the body. If an abnormal heart rhythm is suspected, EKG or longer-term cardiac monitoring can better characterize how frequently the heart is beating in an abnormal rhythm. Abnormalities identified in the cardiac testing may prompt further evaluation, medical management or cardiology procedures to reduce the risk of heart attack or stroke and to in improve the overall cardiac function.

Laboratory evaluation for patients with vascular cognitive impairment focuses both on medical conditions that can have a detrimental effect on thinking and memory and on better characterization of stroke risk factors. As discussed above, risk factors include diabetes, high blood pressure, elevated cholesterol and smoking. Less commonly, patients may have a disorder that makes their blood prone to clotting.

What treatments exist for vascular cognitive impairment?

Medication
Several studies have demonstrated a beneficial effect of cholinesterase inhibitors (donepezil, galantamine or rivastigmine) for patients with vascular cognitive impairment, and we commonly prescribe these medications to provide symptomatic treatment.

Taking an aspirin each day may reduce your risk of heart attack and stroke. You should discuss with your primary care physician at what age you should begin taking a low daily dose (typically 81 mg) of aspirin. Individuals diagnosed with atrial fibrillation or blood clotting disorders may require stronger blood thinners. People who have coronary artery stents or other medical indications may be advised to take aspirin and an additional medication. It is important that you talk to your primary care doctor about which recommendation is right for you.

Non-medication strategies
Memory deficits in people with vascular cognitive impairment.typically involve problems with retrieval. Reminders, cues or placing a question in context may help your loved one to successfully recall information. Executive problems (difficulties with focusing attention, problems with multitasking and problems with mental sequencing) suggest specific strategies that may be beneficial. For those with attention difficulties, reducing environmental distractions may help their concentration. People having problems with mental sequencing are likely to benefit from “checklists” or more detailed written instructions that can be used as a “crutch.” Problems with multitasking suggest that a person may be more successful at tackling tasks in sequence (one after another) rather than starting multiple projects or tasks simultaneously.
Language deficits following stroke (aphasia) may benefit from structured speech therapy. This may be prescribed by your physician.

Surgical interventions
If a significant arterial narrowing or blockage is identified, this may be amenable to surgical or to endovascular intervention, such as carotid endarterectomy or carotid artery stenting

Lifestyle modifications
There are several lifestyle choices that can reduce your risk of cognitive impairment, and many also have been shown to reduce your risk of stroke. All of these choices work in concert to help improve your likelihood of successful aging. Learn more >>