Diagnosis of dementia is clinical in nature. Testing is usually done by a specialist, starting with a thorough history, a detailed medical and neurologic examination, and a formal mental status exam, including cognitive testing (Chertkow et al., 2013). The goal is to determine if there has been a cognitive change, and if so, whether it indicates the onset of dementia or the presence of a disease, infection, drug interaction, or anything else that may cause a cognitive change.
The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM-5), defines dementia (also known as major neurocognitive disorder) as a significant decline in 1 or more cognitive domains that interferes with a person’s independence in daily activities. The 6 cognitive domains identified in the DSM-5 are:
- complex attention,
- executive function,
- learning and memory,
- perceptual motor function, and
- social cognition. (USPSTF, 2020)
Screening is a method for detecting dysfunction before an individual would normally seek medical care. Ideally, screening identifies very early signs of dementia and refers clients who may need a more thorough cognitive assessment. Screening can also identify changes associated with reversible causes and treat conditions that may contribute to cognitive decline (Yang et al., 2016).
The Affordable Care Act directs clinicians to conduct an assessment of possible cognitive impairment in Medicare patients during their Annual Wellness Visit. As many as 29% to 76% of patients with dementia are unrecognized in the primary care setting. Screening usually involves asking patients to perform a series of tasks that assess at least one cognitive domain (USPSTF, 2020, February 25).
Neurocognitive Screening Tools
There are many screening tools that assess cognitive change, although no one tool is recognized as the best brief assessment to determine if a full dementia evaluation is needed (Alzheimer’s Association, 2020b). Screening tests are not intended to diagnose mild cognitive impairment or dementia; a positive screening test result should lead to additional testing. This can include blood tests, radiology examinations, or a neuropsychologic evaluation to confirm the diagnosis of dementia and determine its subtype (USPSTF, 2020, February 25).
The most widely used tools are the Mini Mental State Examination and the Montreal Cognitive Assessment. The Mini Mental State Exam (MMSE) is a 30-point instrument with 11 items that has been studied in various populations. Although sensitivity and specificity vary depending on the patient's age and education level, a general cut point of 23/24 or 24/25 is appropriate for most primary care populations (USPSTF, 2020, February 25).
The Montreal Cognitive Assessment is often used to assess mild cognitive impairment. It is a 30-point test that assesses short term memory recall, visuospatial abilities, and several aspects of executive function. It takes about 10 minutes to complete with a score of 26 or above considered normal.
Other screening instruments include the Clock Drawing Test, Mini-Cog Test, Memory Impairment Screen, Abbreviated Mental Test, Short Portable Mental Status Questionnaire, Free and Cued Selective Reminding Test, 7-Minute Screen, Telephone Interview for Cognitive Status, and Informant Questionnaire on Cognitive Decline in the Elderly (USPSTF, 2020, February 25).
For non-clinicians, family, and friends, a mental status screen such as the AD8 Dementia Screening Interview can be useful. This tool looks at whether there has been a change or no change in:
- Interest in hobbies/activities
- Perseveration (repeating things over and over)
- Trouble learning how to use a tool or device
- Forgetting the month or year
- Trouble handling finances
- Trouble remembering appointments
- Daily problems with thinking or memory (Galvin et al., 2007)
Limitations of Neurocognitive Screens
Despite a large body of evidence examining cognitive screening instruments, most instruments have been tested in only a few well-designed studies. The tests most likely relevant to screening in primary care are very brief instruments, with an administration time of 5 minutes or less (USPSTF, 2020, February 25).
Mini Mental State Examination and the Montreal Cognitive Assessment tests have limitations, namely, they are not very sensitive to mild impairment, particularly in conditions other than Alzheimer’s disease. The MMSE shows education and language/cultural bias (Yang et al., 2016) and both tools may be impractical as screening tools because they take at least 10 minutes to complete.
Other limitations of neurocognitive screening tools can be one or more of the following:
- Language barriers
- Cultural competence and cultural differences
- How the questions are asked
- The validity of questions
- How much time the client is given to answer
- Comfort with the person giving the test
- Your knowledge of a person’s baseline—whether something is normal for that person
Developing an effective dementia screening tool is challenging because the assessment of cognitive deficits is time-consuming and requires specialized knowledge and strong familiarity with neurologic diseases; inaccurate diagnoses are common (Saito et al., 2014). Because of these obstacles, the U.S. Preventive Services Task Force has recommended that, for cognitive impairment in older adults, current evidence is insufficient to assess the balance of benefits and harms of screening for cognitive impairment (USPSTF, 2020, February 25).
UCSF Brief Clinical Index
For clinicians, differentiating between the subtle cognitive declines associated with normal aging and those that signify early dementia can be difficult. To help clinicians better understand the progression of Alzheimer’s disease, researchers at the University of California at San Francisco developed a brief clinical index. The index utilizes 8 items:
Gender, four questions regarding caregiver report of the patients’ behaviors (stubborn/resists help and upset when separated) and functional status (difficulty shopping alone and forgets appointments), and three items focusing on ability to complete basic cognitive tasks (10-item list word recall, orientation to time and place and clock draw test).
Researchers use the brief clinical index to predict whether 382 older adults diagnosed with a certain type of mild cognitive impairment would progress to probable Alzheimer’s disease within 3 years. They also used other measures, including demographics, comorbid conditions, caregiver report of participant symptoms and function, and participant performance on individual items from basic neuropsychological scales. In this study, subjects had a mean age of 75 years and 43% progressed to probable Alzheimer’s disease within 3 years.
Important predictors of progression included being female, resisting help, becoming upset when separated from a trusted caregiver, difficulty shopping alone, forgetting appointments, number of words recalled from a 10-word list, orientation, and difficulty drawing a clock. Fourteen percent of subjects with low-risk scores converted to probable Alzheimer's disease over 3 years, compared to 51% of those with moderate risk scores and 91% of those with high-risk scores.
Source: Lee et al., 2014
Alerting Healthcare Personnel to Changes in a Client’s Cognition
If you are working with a client and notice or suspect a change in mental status, try to determine whether your client is operating at his or her normal level or whether something has changed. If you notice something different in the person’s behavior or demeanor—especially if the change is sudden—report your concerns to the nursing staff immediately. They will assess the client and decide on the next course of action.