What are common causes of MCI and how does it differ from typical aging?
There are many causes of MCI, including neurodegenerative, vascular, metabolic, psychiatric, and traumatic etiologies. The most common cause of MCI is Alzheimer’s disease (AD). The most common symptom of MCI is episodic memory (EM) impairment. This is unsurprising given that AD is the most common cause and EM impairment is the signature AD characteristic. That being said, clinicians should be aware that AD can present in atypical ways in which memory impairment is not an early symptom. The challenge to clinicians is differentiating cognitive changes associated with pathology versus those that occur with typically aging adults. Older adults who experience changes in cognition typically have slower processing speeds, do not divide attention as efficiently as they once did, and have difficulty ordering two or more events. These adults, however, do not have an episodic memory deficit. These changes differentiate individuals with AD-related MCI from healthy older adults (Bayles et al., 2020; Sabbagh et al., 2010).
The four neurobehavioral criteria that define MCI (American Psychiatric Association, 2013) are:
- Concern regarding a change in cognition, compared with prior level, through self-report or the report of an informant or clinician.
- Impairment in one or more cognitive domains that is lower than expected for the patient’s age and education.
- Preservation of independence in functional abilities though the individual may be less efficient, prone to making errors, and need more time for task completion.
- Not demented: The cognitive and behavioral changes are insufficient to significantly interfere with social or occupational functioning.
Although most individuals experience slight cognitive changes as they age, those with MCI often experience cognitive changes that are of concern to the individual and/or family, and have objectively confirmed impairment in one or more cognitive domains (e.g., language or spatial/visual perception). McKhann (2011) offered that “[t]here are no exact transition points that define when an individual has progressed from the MCI phase to the dementia phase. It is a question of clinical judgment.” Individuals with MCI do not have dementia and can independently perform activities of daily living (ADLs). When ADLs are impaired, a “major neurocognitive disorder” may be considered (American Psychiatric Association, 2013).
This ATE is an excerpt from the course, 20Q: Mild Cognitive Impairment - The SLP’s Role in Service Delivery, authored by Kim McCullough, PhD, CCC-SLP and Anne Hunter Cox.