Friday, August 6, 2010

Virtual Reality Technology and Alzheimer's Disease

The use of virtual reality technology in the assessment, study of, and possible assistance in the rehabilitation of memory deficits associated with patients with Alzheimer disease.


Alzheimer's disease is the common cause of dementia, and is particularly common in older people. Because it is the most common cause of dementia, Alzheimer's disease is commonly equated with the general term dementia. However, there are many other causes of dementia. Alzheimer's disease is therefore a specific form of dementia having very specific microscopic brain abnormalities.

Alzheimer disease is not merely a problem of memory. Additional mental and behavioral problems often affect people who have the disease, and may influence quality of life, caregivers, and the need for institutionalization.

Depression for example affects 20–30% of people who have Alzheimer’s, and about 20% have anxiety. Psychosis (often delusions of persecution) and agitation/aggression also often accompany this disease. Common symptoms and comorbidities include:

• Mental deterioration of organic or functional origin

• Loss of cognitive ability in a previously-unimpaired person, beyond what might be expected from normal aging. Areas particularly affected include memory, attention, judgement, language and problem solving.

• Loss (usually gradual) of mental abilities such as thinking, remembering, and reasoning. It is not a disease, but a group of symptoms that may accompany some diseases or conditions affecting the brain.

• Deteriorated mental state due to a disease process and the result from many disorders of the nervous system.

• Cognitive deficit or memory impairment due to progressive brain injury.

Distinguishing Alzheimer's disease from other causes of dementia is not always as easy and straightforward as defining these terms. In practice, people and their disorders of behaviour, or behaviours of concern are far more complex than the simple definitions sometimes provided.

Establishing patient history, abilities, the natural course of disorder development such as that involving short-term memory, speech and language, personality, decision-making and judgment, and others is often needed in the diagnosis of the disease. Routine diagnostic steps therefore include a careful history, mental status screening, laboratory and imaging studies, and neuropsychologic testing.

Differential diagnosis of Alzheimer's disease

It is sometimes difficult to differentiate dementia caused by Alzheimer's from delirium and in addition several features distinguish dementia from depression, but the two can coexist and the distinction may be uncertain.

Whilst prominent motor signs such as Gait disturbance is a characteristic feature of patients with vascular dementia - In contrast, the NINCDS-ADRDA criteria for Alzheimer's disease state that: `gait disturbance at the onset or very early in the course of the illness' makes the diagnosis of probable Alzheimer's disease uncertain or unlikely. However, clinical studies suggest that gait disturbance is not restricted to the later stages of Alzheimer's disease. Also, studies have identified abnormalities of gait and balance in patients with early Alzheimer's disease(1).

It had been thought that Dementias without prominent motor signs included Alzheimer's disease, frontotemporal dementia, and Creutzfeld-Jakob, and others and the clinical pattern of gait disturbance in patients with early Alzheimer's disease has attracted less attention to date.


Differential diagnosis between the types of dementia and treatments available for Alzheimer's - while limited in their effectiveness usually have best patient outcomes when begun early in the course of the disease. Diagnosis and/or diagnostic tools include:

Taking medical history.

Physical examination including evaluations of hearing and sight, as well as blood pressure and pulse readings, etc.

Standard laboratory tests including blood and urine tests designed to help eliminate other possible conditions.

Neuropsychological testing including assessing memory, problem-solving, attention, vision-motor coordination and abstract thinking, such as performing simple calculations.

Brain-imaging or structural brain scan such as CT or MRI to help rule out brain tumors or blood as the reason for symptoms and more recently

The use of virtual reality

The use of virtual reality technology in the assessment, study of, and possible assistance in the rehabilitation of memory deficits associated with patients with Alzheimer disease.

Using virtual reality to simulate real-word environments and test patient’s ability to navigate these environments. Work has been carried out to compare previously described real-world navigation tests with a virtual reality version simulating the same navigational environment (2). Authors of this research work conclude that virtual navigation testing reveals deficits in aging and Alzheimer disease that are associated with potentially grave risks to patients and the community.

In another study in the United Kingdom (3), researchers’ aimed to examine the feasibility of virtual reality technology for use by people with dementia (PWD). Data was obtained directly from six PWD regarding their experiences with a virtual environment of a large outdoor park. A user-centered method was developed to assess:

(a) presence;
(b) user inputs;
(c) display quality;
(d) simulation fidelity; and
(e) overall system usability.

The extent to which PWD could perform four functional activities in the virtual enviroment was also investigated (e.g., mailing a letter). In addition, physical and psychological well-being of PWD while interacting with the virtual environment was assessed objectively by recording heart rate during the virtual reality sessions and subjectively with discrete questionnaire items and real-time prompts.

(1) Gait disturbance in Alzheimer's disease: a clinical studyS.T. O'Keeffe, H. Kazeem, R.M. Philpott, J.R. Playfer, M. Gosney, M. Lye July, 1996

(2) NEUROLOGY 2008;71:888-895
Detecting navigational deficits in cognitive aging and Alzheimer disease using virtual reality
Laura A. Cushman, PhD, Karen Stein and Charles J. Duffy, MD, PhD
From the Departments of Neurology, Brain and Cognitive Sciences, Neurobiology and Anatomy, Ophthalmology, and Psychiatry (L.A.C.) and Center for Visual Science,
The University of Rochester Medical Center, Rochester, NY.

(3) Flynn D, van Schaik P, Blackman T, Femcott C, Hobbs B, Calderon C.
School of Social Sciences and Law, The University of Teesside, Middlesbrough, United Kingdom

1 comment:

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