Clinical Assessment of Dementia: A Practical Evidence-Based Approach to Diagnosis

Abstract

Background: Dementia is a heterogeneous clinical syndrome characterized by progressive cognitive decline that interferes with independent functioning. Although advances in neuroimaging, fluid biomarkers, molecular diagnostics, and genetic testing have improved etiological classification, dementia remains fundamentally a clinical diagnosis. Biomarker findings must therefore be interpreted within the context of the patient’s cognitive, functional, behavioural, neurological, medical, and psychosocial presentation. Objective: This narrative review provides a practical, evidence-based framework for the comprehensive clinical assessment of adults presenting with suspected dementia, with emphasis on translating contemporary diagnostic principles into routine clinical practice across primary care, geriatrics, neurology, psychiatry, and memory-clinic settings. Methods: Current clinical guidelines, consensus criteria, validated assessment instruments, and contemporary evidence concerning dementia diagnosis were narratively synthesized. The review examines history taking and collateral information, characterization of cognitive symptom profiles, functional assessment, neurological examination, early warning signs, longitudinal progression, behavioural and psychological symptoms, differential diagnosis, cognitive screening, laboratory and neuroimaging evaluation, biomarkers, and emerging digital and artificial-intelligence technologies. Results: Accurate assessment requires integration of multiple complementary sources of information rather than reliance on any single test. A detailed history from both the patient and a knowledgeable informant establishes symptom onset, tempo, affected cognitive domains, and change from premorbid functioning. Functional assessment is essential for distinguishing dementia from mild cognitive impairment, while neurological and behavioural findings assist with syndrome differentiation, severity determination, safety evaluation, and identification of reversible or contributing conditions. Serial assessment is particularly valuable because longitudinal changes in cognition, function, and behaviour may be more diagnostically informative than a single evaluation. Biomarkers and artificial intelligence can improve diagnostic confidence, subtype classification, and monitoring but should complement rather than replace clinical reasoning and patient-centered judgment. Conclusion: Comprehensive clinical assessment remains the cornerstone of timely and accurate dementia diagnosis. A systematic, multidisciplinary, and patient-centered approach integrating history, cognition, function, behaviour, neurological examination, and appropriately selected investigations provides the strongest basis for etiological diagnosis, individualized management, caregiver support, safety planning, and longitudinal care. Keywords: dementia; cognitive impairment; clinical assessment; diagnosis; functional assessment; neurological examination; neuropsychiatric symptoms; biomarkers; artificial intelligence; patient-centered care.