Question
What are the Stages of Alzheimer’s Disease?
Answer
Alzheimer’s disease progresses through several stages, each characterized by varying degrees of cognitive and functional decline. Understanding these stages is crucial for diagnosis, treatment, and management.
Stages of Alzheimer’s Disease
Preclinical Alzheimer’s Disease
Stage 1 and 2: These are preclinical stages where individuals may have amyloid biomarkers but no noticeable symptoms. Stage 1 is defined by the absence of symptoms, while Stage 2 includes subjective cognitive complaints, transitional cognitive declines, and neurobehavioural symptoms (Kiselica, Kaser and Benge, 2020; Kiselica, 2021; Kiselica, Kaser and Benge, 2020).
Mild Cognitive Impairment (MCI)
Early MCI (EMCI) and Late MCI (LMCI): These stages involve noticeable cognitive decline that does not yet interfere significantly with daily life. EMCI is an earlier phase, while LMCI indicates more pronounced impairment (Shamrat et al., 2023; Mora-Rubio et al., 2023).
Alzheimer’s Disease (AD)
Mild AD: Cognitive decline becomes more apparent, affecting memory, reasoning, and daily tasks.
Moderate AD: Symptoms worsen, with increased memory loss, confusion, and difficulty with language and reasoning.
Severe AD: Individuals lose the ability to respond to their environment, communicate, and eventually control movement (Therriault et al., 2022; Bringas et al., 2020; Jutten et al., 2020).
Diagnostic Tools and Biomarkers
Imaging and Biomarkers: PET scans, cerebrospinal fluid analysis, and MRI are used to detect amyloid plaques and brain atrophy, aiding in the identification of preclinical stages (Therriault et al., 2022; Mora-Rubio et al., 2023).
Neuropsychological Tests: These tests help assess cognitive decline across different stages, with varying sensitivity depending on the stage (Jutten et al., 2020).
Alzheimer’s disease progresses from preclinical stages with no symptoms to severe dementia. Early detection through biomarkers and imaging, along with cognitive assessments, is essential for managing the disease effectively. Understanding these stages helps in tailoring interventions and improving patient care.
References
Therriault, J., Zimmer, E., Benedet, A., Pascoal, T., Gauthier, S., & Rosa-Neto, P., 2022. Staging of Alzheimer’s disease: past, present, and future perspectives.. Trends in molecular medicine. https://doi.org/10.1016/j.molmed.2022.05.008
Shamrat, F., Akter, S., Azam, S., Karim, A., Ghosh, P., Tasnim, Z., Hasib, K., De Boer, F., & Ahmed, K., 2023. AlzheimerNet: An Effective Deep Learning Based Proposition for Alzheimer’s Disease Stages Classification From Functional Brain Changes in Magnetic Resonance Images. IEEE Access, 11, pp. 16376-16395. https://doi.org/10.1109/ACCESS.2023.3244952
Bringas, S., Salomón, S., Duque, R., Lage, C., & Montaña, J., 2020. Alzheimer’s Disease stage identification using deep learning models. Journal of biomedical informatics, pp. 103514. https://doi.org/10.1016/j.jbi.2020.103514
Kiselica, A., Kaser, A., & Benge, J., 2020. Empirically defining preclinical Alzheimer’s disease in the era of biomarkers. Alzheimer’s & Dementia, 16. https://doi.org/10.1002/alz.036190
Mora-Rubio, A., Bravo-Ortiz, M., Arredondo, S., Saborit-Torres, J., Ruz, G., & Tabares-Soto, R., 2023. Classification of Alzheimer’s disease stages from magnetic resonance images using deep learning. PeerJ Computer Science, 9. https://doi.org/10.7717/peerj-cs.1490
Kiselica, A., 2021. Empirically defining the preclinical stages of the Alzheimer’s continuum in the Alzheimer’s Disease Neuroimaging Initiative. Psychogeriatrics, 21. https://doi.org/10.1111/psyg.12697
Jutten, R., Sikkes, S., Amariglio, R., Buckley, R., Properzi, M., Marshall, G., Rentz, D., Johnson, K., Teunissen, C., Van Berckel, B., Van Der Flier, W., Scheltens, P., Sperling, R., & Papp, K., 2020. Identifying Sensitive Measures of Cognitive Decline at Different Clinical Stages of Alzheimer’s Disease. Journal of the International Neuropsychological Society, 27, pp. 426 – 438. https://doi.org/10.1017/S1355617720000934
Kiselica, A., Kaser, A., & Benge, J., 2020. An Initial Empirical Operationalization of the Earliest Stages of the Alzheimer’s Continuum.. Alzheimer Disease & Associated Disorders. https://doi.org/10.1097/WAD.0000000000000408
