Cognitive impairment refers to changes in memory, attention, language, thinking, orientation, or the ability to plan and carry out everyday activities. Changes may be mild or substantial, temporary or persistent, stable or progressive.
Cognitive impairment is not a single diagnosis and does not always mean dementia. It can result from a range of neurological, mental and physical health conditions, medication effects, sleep disturbance or substance use. Identifying when the changes began, how they are developing and how they affect daily life helps guide assessment and support.
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Changes that may need attention
- frequently forgetting recent events, arrangements or familiar information;
- difficulty concentrating, sustaining attention or switching between tasks;
- difficulty finding words, understanding speech, reading or writing;
- problems with planning, familiar tasks, finances or taking medication;
- becoming disorientated in time or in a familiar place;
- changes in visual-spatial skills or recognising objects;
- reduced ability to carry out familiar daily activities independently.
An occasional memory lapse or tiredness after exertion does not establish a disorder. The onset, persistence and progression of changes, and their effect on independence, education, work or safety, are important.
Possible causes
Cognitive changes may have one or several causes:
- neurological conditions — neurodegenerative disease, stroke, traumatic brain injury, epilepsy, inflammatory disease or other nervous system conditions;
- mental health conditions — depression, severe anxiety, psychotic disorders or the effects of severe stress;
- physical and metabolic causes — infection, thyroid dysfunction, particular vitamin deficiencies, changes in glucose or electrolytes, and other health conditions;
- medication — including medicines with sedative or anticholinergic effects, particularly when several medicines are combined;
- sleep and sensory difficulties — persistent sleep deprivation, sleep apnoea, or substantial hearing or sight impairment;
- alcohol and other substances — acute effects, long-term risky use, a substance use disorder or withdrawal.
Hereditary factors may contribute to some conditions, but family history does not determine a diagnosis on its own. Upbringing is not regarded as a universal cause of cognitive impairment.
Sudden changes require urgent assessment
Sudden confusion, disorientation or a marked change in attention over hours or days may indicate delirium, stroke, infection, medication effects or another acute condition. Immediate help is also needed for new weakness on one side of the body, difficulty speaking, a seizure, loss of consciousness, a sudden severe headache or changes after a head injury. In Ukraine, call 103 or 112.
Initial assessment
A GP can be the first point of contact. The clinician asks about the symptoms and their effect on daily life, their onset and rate of change, previous illness or injury, medication, sleep, mood, alcohol or other substance use, and checks hearing and sight when relevant. With the person's consent, information from someone who knows them well can be helpful.
Assessment includes an appropriate physical and neurological examination. A brief validated cognitive instrument can help describe strengths and difficulties, but one normal score does not rule out cognitive impairment or dementia, and a low score does not establish the cause by itself.
Laboratory tests, neuropsychological assessment and imaging
Blood tests, urine tests and other investigations are selected according to the history, examination and likely causes. They can help identify potentially reversible factors, but the same set of investigations is not required for everyone.
MRI or CT is used when clinically indicated, for example to look for structural causes or help determine a suspected dementia subtype. Imaging does not replace clinical assessment, and a normal scan does not always exclude disease. Detailed neuropsychological assessment may be useful when it is unclear whether impairment is present, what may be causing it or which pattern of cognitive strengths and difficulties needs support.
Depending on the situation, a GP may involve a neurologist, psychiatrist, geriatrician, neuropsychologist or another relevant professional. Rapidly progressive symptoms require urgent referral to an appropriate specialist service.
When to seek advice and available support
A routine appointment is appropriate when a person or those close to them notice persistent changes in memory, attention, language or behaviour, especially if the changes are progressing or affecting work, education, everyday tasks, driving, medication use or financial decisions. Universal repeated cognitive screening is not needed in the absence of symptoms or a clinical indication.
Support depends on the cause. It may include reviewing medication, treating a physical or mental health condition, improving sleep, rehabilitation, cognitive strategies, adapting the home environment and supporting family members. If a neurodegenerative condition is confirmed, the specialist discusses available treatment, safety, support for independence and an ongoing follow-up plan.