From the Guidelines
Screening for pre-formal Alzheimer's disease is recommended for individuals with memory complaints, those with a family history of dementia, and adults over 65 years of age, using cognitive assessments and emerging biomarkers, as early detection allows for timely intervention and improved outcomes. The primary screening method involves cognitive assessments such as the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), or the Mini-Cog test, which evaluate memory, language, attention, and problem-solving abilities, as suggested by 1. These tests typically take 5-30 minutes to administer in a clinical setting. Additionally, a thorough medical history, physical examination, and laboratory tests (including complete blood count, thyroid function, vitamin B12, and metabolic panel) should be performed to rule out other causes of cognitive decline.
Brain imaging with MRI or CT scan may be used to identify structural changes or rule out other conditions. For more definitive diagnosis, specialized tests like PET scans using amyloid or tau tracers can detect characteristic protein deposits in the brain, as discussed in 1. Early screening is valuable because it allows for timely intervention with medications like cholinesterase inhibitors (donepezil, rivastigmine, galantamine) or memantine, which may temporarily improve symptoms or slow progression. Early detection also enables patients and families to plan for future care needs and access support services while the patient can still participate in decision-making.
The use of emerging biomarkers, such as blood-based biomarkers, may also play a crucial role in early detection, as highlighted in 1. Furthermore, recent studies, such as 1, emphasize the importance of early diagnosis and recruitment of individuals with pre-formal Alzheimer's disease into clinical trials, to improve participation and access to potentially helpful interventions. Key considerations for screening and early detection include:
- Cognitive assessments, such as MMSE, MoCA, or Mini-Cog test
- Emerging biomarkers, such as blood-based biomarkers
- Thorough medical history, physical examination, and laboratory tests
- Brain imaging with MRI or CT scan
- Specialized tests, such as PET scans using amyloid or tau tracers
- Early intervention with medications, such as cholinesterase inhibitors or memantine
- Access to support services and planning for future care needs.
From the Research
Indications for Screening
- Pre-formal Alzheimer's disease (AD) can be indicated by subjective cognitive decline (SCD), which is considered the earliest symptomatic manifestation of preclinical AD 2
- Cognitive screening is often a first step to document cognitive status of patients suspected of having AD 3
- Individuals with SCD may benefit from non-pharmacological interventions (NPIs) for the secondary prevention of AD 2
Methods for Screening
- Neuropsychological tests such as the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) are commonly used for screening cognitive dysfunction of AD 4
- The History-based Artificial Intelligence-Show Chwan Assessment of Cognition (HAI-SAC) is a novel screening neuropsychological test that incorporates assessments of core memory deficits typical of early AD and an interview on memory function with an informant 3
- HAI-SAC has been shown to outperform other tests in differentiating cognitively unimpaired individuals from patients with mild cognitive impairment (MCI) or dementia of Alzheimer's type (DAT) 3
- Cognitive training and psychological interventions may be beneficial for cognitive function and psychological well-being in individuals with SCD 2
- Category Fluency, Word List Delayed Recall, and Trail Making Test are sensitive to decline in early clinical stages of AD, while the Mini-Mental State Examination may not capture decline until later stages 5
Characteristics of Screening Tests
- MoCA has a higher diagnostic odds ratio (DOR) and better performance than MMSE in screening dementia associated with AD 4
- HAI-SAC has acceptable internal consistency and a strong correlation with other common screening tests 3
- The performance of HAI-SAC is less than one quarter that of the Cognitive Abilities Screening Instrument (CASI) and half that of MoCA 3