A common misconception: “If dementia isn’t curable, why bother with a diagnosis?” The answer lies on several levels:
- To rule out reversible causes: About 10 percent of all cognitive disorders have treatable causes—vitamin B12 deficiency, thyroid disease, normal-pressure hydrocephalus, medication side effects, and depression in older adults.
- Identifying the type of dementia: Alzheimer’s disease, vascular dementia, Lewy body dementia, and frontotemporal dementia each have different treatments, disease courses, and precautions.
- Explore treatment options: The new anti-amyloid antibodies are effective only in cases of confirmed Alzheimer’s pathology and only in the early stages. Read more in the article on dementia treatment.
- Enabling advance planning: Power of attorney, living will, financial and family planning—all of these require legal capacity, which is lost as dementia progresses.
- Ending uncertainty: Many families live with years of uncertainty—a structured dementia diagnosis provides relief even when it is difficult to accept.
→ For an overview of dementia disorders: Dementia in Older Adults.
Modern dementia diagnosis is a step-by-step, interdisciplinary process. It typically proceeds as follows:
Level 1: Primary Care Physician
The primary care physician is the first point of contact. They conduct a structured interview, use brief tests (MMSE, clock drawing test, DemTect), order basic laboratory tests, and decide whether to refer the patient for further evaluation. If the findings are clear, the primary care physician can also initiate basic drug therapy themselves.
Level 2: Memory Clinic, Neurologist, Psychiatrist, Geriatrician
Specialist evaluation includes detailed neuropsychological testing, imaging (MRI), and, if necessary, cerebrospinal fluid biomarkers. Which specialist is responsible depends on the predominant aspect—in cases of clear suspicion of dementia, it is often neurology or a memory clinic; in cases of multimorbidity and accompanying psychiatric symptoms, it is often geriatrics or psychiatry. It is often difficult to distinguish between dementia and depression—a diagnostic field in its own right with up to 30 percent misdiagnosis rates.
Level 3: Specialized Centers
For biomarker-based diagnostics prior to anti-amyloid therapy, for unclear or atypical cases, for early-onset dementia (before age 65), or for patients interested in research, there are specialized centers at university hospitals and larger medical facilities.
1. The Structured Interview
The most important and most underestimated component. Topics:
- Onset and progression of symptoms—gradual or acute?
- Which areas are affected—memory, language, orientation, behavior?
- Coping with daily life—what can the person still do, and what can’t they do?
- Accompanying symptoms—mood, sleep, hallucinations, movement disorders?
- Pre-existing conditions and medications—especially with regard to polypharmacy in older adults
- Family medical history
- Living circumstances — social, emotional, financial
The key is obtaining the history from family members and caregivers. Patients with early-stage dementia often downplay or fail to recognize their deficits. Only by involving family members can a complete picture be obtained.
2. Cognitive tests
Mini-Mental State Examination (MMSE)
The classic screening test. Maximum score of 30 points. Assesses orientation, memory, attention, language, and writing ability. A score below 24 is suspicious. Limitation: not sensitive enough to detect mild or early-onset deficits, especially in highly educated patients who compensate for deficits for a long time. For early-stage cases, a diagnosis of mild cognitive impairment (MCI) is crucial.
Montreal Cognitive Assessment (MoCA)
More sensitive than the MMSE; currently considered the gold standard in clinical screening. Maximum score: 30 points. A score below 26 is suspicious. Particularly effective for early detection and executive function deficits.
Clock Drawing Test
Simple and surprisingly discriminatory. The patient is asked to draw a clock with all the numbers and to mark a specific time (e.g., 11:10). The result assesses many cognitive domains simultaneously—spatial orientation, planning, and numerical comprehension.
DemTect
A test developed in Germany, well-validated, and sensitive even to mild impairments. Covers word learning, number conversion, number sequences, and delayed recall. Maximum score: 18 points.
Comprehensive neuropsychological testing
Conducted at memory clinics or specialized centers. Takes one to three hours. Provides a differentiated assessment of individual cognitive domains—memory, executive functions, language, spatial ability, and attention. Particularly valuable for atypical or early-stage cases.
→ For structured classification of early-stage cases: Mild Cognitive Impairment (MCI).
3. Laboratory
Laboratory testing is primarily used to rule out reversible causes. Standard tests include:
- Complete blood count, CRP, ESR
- Electrolytes, kidney and liver function tests
- TSH (thyroid function)
- Vitamin B12, folic acid
- Vitamin D
- Blood sugar or HbA1c — also relevant for diabetes in older adults, which increases the risk of dementia
- If clinically suspected: HIV, syphilis, Lyme disease, heavy metals
A vitamin B12 deficiency, thyroid disease, or severe hyponatremia can trigger cognitive symptoms ranging up to dementia-like symptoms—and are treatable.
4. Medication Review
An essential step. Many medications cause or exacerbate cognitive symptoms—a common problem associated with polypharmacy in older adults:
- Benzodiazepines and Z-drugs
- Strongly anticholinergic medications (amitriptyline, oxybutynin, older antihistamines)
- Tricyclic antidepressants
- Opioids at higher doses
- Certain antiepileptic drugs
- Corticosteroids at higher doses
A structured medication review is mandatory prior to a definitive diagnosis of dementia.
→ About the deprescribing process: Safely reducing medications (deprescribing).
5. Imaging
Head MRI
The gold standard in dementia evaluation. MRI addresses several issues simultaneously:
- Atrophy patterns (particularly the hippocampus in Alzheimer’s disease)
- Vascular lesions (strokes, microcirculatory damage) — also relevant in the context of stroke in older adults
- Normal-pressure hydrocephalus — a treatable cause with a typical triad: gait disturbance, incontinence, cognitive impairment
- Tumors, hemorrhages, inflammation
- Microbleeds (important prior to anti-amyloid therapy)
Head CT
If MRI is not possible (pacemaker, severe claustrophobia). Less sensitive to atrophy and subtle vascular changes.
FDG-PET
Shows regional glucose metabolism—a reduction in the temporoparietal regions is typical in Alzheimer’s disease. Used in special cases and in research settings. Information on nuclear medicine imaging: Positron Emission Tomography (PET).
Amyloid-PET
Direct detection of amyloid deposits. Not widely available in Germany; expensive; usually performed at specialized centers. An alternative to cerebrospinal fluid (CSF) analysis.
6. Cerebrospinal Fluid Biomarkers
For the past 10 to 15 years, lumbar puncture has been the gold standard for early detection of Alzheimer’s disease. The following are measured:
- Beta-amyloid 1-42: Reduced in cerebrospinal fluid in Alzheimer’s disease (paradoxically: high levels deposited in the brain, but low levels available in the cerebrospinal fluid).
- Total tau: Elevated in cases of neuronal cell loss.
- Phospho-tau (p-tau): Specific to Alzheimer’s-typical tau pathology.
The combination of these three values—also known as the CSF triple—allows Alzheimer’s disease to be distinguished from other forms of dementia with over 90 percent certainty.
A lumbar puncture is an established, safe procedure. Modern techniques make headaches after the puncture rare. The decision to perform a puncture should be made in specialized centers—in cases of mild clinical uncertainty, prior to anti-amyloid therapy, in cases of atypical disease progression, and in cases of early-onset dementia.
7. Blood-Based Biomarkers — The Breakthrough Since 2024
The previous limitation of biomarker diagnostics lay in the need for a lumbar puncture or PET scan—both of which are complex and not universally available. Since 2024, blood-based biomarkers have developed rapidly:
- Plasma-based p-Tau217 has shown over 90 percent agreement with CSF and PET results in studies
- Combinations of various plasma biomarkers (amyloid ratio 42/40, p-Tau181, p-Tau217) further increase accuracy
- Simple blood draw instead of a lumbar puncture or imaging
- Gradual introduction into routine clinical practice, primarily in specialized centers
The significance of this development for dementia diagnostics is historic. If the data to date are confirmed on a broad scale, early detection of Alzheimer’s disease could become significantly more accessible, earlier, and more widespread in the coming years. However, clinical judgment remains central—the biomarker does not replace the physician’s assessment; it complements it.
8. Genetics
In most cases, not part of routine diagnostics. Relevant for:
- Early-onset dementia before age 65 with a family history (APP, PSEN1, PSEN2 mutations)
- Prior to anti-amyloid therapy to determine the APOE genotype (ε4/ε4 is usually a contraindication due to increased ARIA risk)
- Frontotemporal dementias with a family history (C9orf72, GRN, MAPT)
The art of dementia diagnosis lies not in individual values, but in their integration. A slightly abnormal MMSE score with no other findings has a completely different significance than the same score in combination with hippocampal atrophy and a positive cerebrospinal fluid biomarker. The diagnosis arises from the interplay of all the information:
- Clinical presentation and course
- Cognitive test profile
- Imaging
- Laboratory exclusion criteria
- Biomarker results
- Social and Biographical Context
It is precisely this integration that makes dementia diagnosis a task best left to specialists—even if individual components can be supported by automated laboratory systems or AI. The holistic perspective remains irreplaceable. The geriatric assessment provides the structural framework for embedding cognitive findings within the broader context of overall health.
A structured dementia diagnosis is never an endpoint, but rather a starting point:
- Medical findings and counseling: A clear and understandable discussion with the patient and their family. Not a cold announcement, but guided interpretation.
- Treatment plan: Basic pharmacological therapy (if indicated), non-pharmacological interventions, and, if applicable, evaluation of suitability for anti-amyloid antibodies. Details on dementia treatment in 2026.
- Advance Planning: Power of attorney for healthcare, living will, and guardianship directive while the patient is still legally competent.
- Care plan and support structures: Care level, day care, home care, self-help groups.
- Further follow-up: Regular reassessment every 6 to 12 months.
→ For an overview of treatment options: Dementia Treatment 2026.
→ For information on Alzheimer’s disease specifically: Alzheimer’s Disease.
Specific triggers:
- Recurrent forgetfulness that interferes with daily life—over weeks and months, not just isolated episodes
- Difficulty orienting oneself in familiar surroundings
- Difficulty finding the right words, which has increased significantly
- Personality changes or social withdrawal — which may also be signs of depression in older adults and need to be distinguished from other conditions
- Difficulty with familiar tasks (cooking, managing finances)
- Concerns expressed by family members, even if the patient denies having any issues
- Personal uncertainty that causes distress
- Major life decisions—surgery, moving, changing a will. Cognitive assessment is part of evaluating surgical risk in older adults.
The first point of contact is the primary care physician, who will refer the patient to a memory clinic, a neurologist, or a geriatrician if necessary. Specialized centers offer interdisciplinary diagnostic services. For older patients with multiple chronic conditions, the geriatric perspective is particularly valuable because it places dementia in the context of overall health—including possible comorbidities such as frailty syndrome, heart failure in older adults, or polypharmacy.
→ For a comprehensive geriatric assessment that structurally integrates cognitive evaluation: Geriatric Assessment.
