What’s New in the Alzheimer’s Disease Spectrum: Diagnosis and Management

Alzheimer’s disease (AD) is an irreversible neurodegenerative disorder characterized by a patient’s activities of daily living (ADL), cognitive decline, and behavioral changes.

There are many hypotheses about the causes of dementia, including the deposition of amyloid plaques. A tau protein that self-replicates and contributes to neurofibrillary tangles. Loss of cells that produce the neurotransmitter acetylcholine; and more recently, genetic variation and inflammatory conditions.^1-7

The cause of AD is not clear, but recent advances in research have further improved our understanding of AD. It is now known that pathophysiological changes begin years before the disease appears clinically and that the AD spectrum ranges from clinically asymptomatic to severely impaired.⁸ In addition, biomarkers have been identified and are beginning to be used to assist in diagnosis. Diagnosis is not based solely on its clinical symptoms, as it has been done so far.

Recognizing the concept of AD as a physiological continuum is essential for the development of diagnostic tools, management strategies, and disease modification therapy (DMT).^8.9

Redefinition of Alzheimer’s disease

In 2011, the National Institute of Neurology, Communication Disorders and Stroke and the Alzheimer’s Disease and Related Disorders Association revised the 1984 AD Standards.^Ten It incorporates scientific advances in this area.^11,12 The following Clinical Dementia Assessment (CDR) from the new criteria describes the progression of clinical disease¹¹:

• Preclinical (early stage): Brain changes may already be progressing, but clinical symptoms are not yet clear.
• Mild cognitive impairment (MCI): Memory symptoms and / or a person’s age and education are greater than normal, but are characterized by other thought problems that do not interfere with his or her independence.
• Alzheimer’s disease (final stage): Symptoms such as amnesia, difficulty finding words, and visual / spatial problems are severe enough to affect their ability to function independently.

The main purpose of the revised standard was to make it flexible enough to be used by clinicians who do not have access to neuropsychological tests, advanced diagnostic imaging, and cerebrospinal fluid analysis, and researchers who have access to these tools. ..⁹ The modified criteria are reliable in the possible diagnosis of AD, showing 81% sensitivity and 70% specificity over more than 12 clinicopathological studies.¹²

The modified diagnostic criteria are intended to incorporate the severity of dementia ranging from the mildest to the most severe.¹² Diagnosis of cognitive impairment should include medical history and knowledgeable sources (caretakers, relatives) obtained directly from the patient in combination with an objective cognitive assessment by “bedside” mental status or neuropsychological examination. there is.¹² If the diagnosis is still unclear, a neuropsychological test should be done.In addition, the documented deficit must contain at least two of the following five areas:¹²:

1. Impaired ability to retrieve and remember new information: repetitive questions and conversations, misplaced belongings, forgotten events and appointments, lost children on familiar routes.
2. Impaired reasoning and processing of complex tasks, impaired judgment: lack of understanding of safety risks, lack of financial management ability, lack of decision-making ability, lack of planning of complex or continuous activities.
3. Impaired visual space ability: Despite excellent acuity, cannot recognize faces and general objects, or cannot find objects in direct vision, cannot operate simple tools, or turn clothes toward the body Is difficult.
4. Language dysfunction (speaking, reading, writing): Difficult to think of common words when speaking, hesitation, speech, spelling, and writing errors.
5. Changes in personality, behavior, or empathy: excitement, impaired motivation and initiative, indifference, loss of motivation, social withdrawal, diminished interest in previous activities, loss of empathy, compulsive or compulsive behavior, social Unacceptable behavioral changes in mood.

It is important to note that the distinction between dementia and MCI depends on the ability to perform normal activities of daily living.¹¹

From the December 2020 issue of Clinical Advisor