What cognitive impairment means
Cognitive impairment describes difficulty with memory, attention, language, visuospatial skills or executive function beyond what is expected for age and education. It exists on a spectrum from subjective cognitive decline (patient reports symptoms but tests are normal) through mild cognitive impairment (MCI — objective deficits not interfering significantly with daily activities) to dementia (deficits severe enough to impair independence in daily tasks). Identifying where a patient falls on this spectrum requires structured assessment rather than symptom counting alone.
Cognitive impairment is not a single disease. It can result from neurodegenerative conditions (Alzheimer's disease, frontotemporal dementia, Lewy body dementia), vascular disease (stroke, chronic hypertension), metabolic or nutritional factors (thyroid dysfunction, vitamin B12 deficiency, chronic liver or kidney disease), medication effects (anticholinergics, sedatives, opioids), mood disorders (depression, anxiety), sleep disturbance, and chronic pain. Many of these contributors are reversible, making accurate identification essential before attributing symptoms to an untreatable neurodegenerative process.
- Subjective decline — patient reports symptoms, tests normal
- Mild cognitive impairment (MCI) — objective deficits, daily function preserved
- Dementia — deficits severe enough to impair independence
- Reversible causes: thyroid, B12, medications, depression, sleep
Related: Cognitive Care → · Dr. Jitendra Knowledge Hub → · ICHD-3 Topic →
Evaluation and reversible causes
Cognitive assessment at Kathmandu Neurology Clinic begins with patient plus informant history — a family member or close companion who observes daily changes provides essential context that self-report alone may miss. History covers onset, tempo (gradual vs sudden vs stepwise), affected domains (memory, language, attention, visuospatial, executive function), functional impact, medication list, mood, sleep, alcohol use and relevant medical history. The pattern of onset and affected domains narrows the differential before any test is performed.
Brief cognitive screening (MoCA or MMSE) quantifies deficits and provides a baseline for follow-up. Targeted blood tests (thyroid function, vitamin B12, fasting glucose, renal function, liver function) exclude metabolic and nutritional contributors. Brain imaging (MRI preferred) is considered when onset is sudden, progression is rapid, focal neurological signs are present, or when the pattern is atypical for common neurodegenerative diseases. Results are discussed transparently with the patient and family, with clear next steps and realistic expectations.
- Patient plus informant history — essential for accurate assessment
- MoCA or MMSE screening — quantifies deficits, baseline for follow-up
- Targeted labs: thyroid, B12, glucose, renal, liver function
- MRI considered for sudden onset, rapid progression, or atypical pattern