Some noteworthy potential ‘pitfall’ symptoms and signs requiring further clarification or interpretation in suspected dementia
| Feature | Clarification/interpretation | Major causes |
| Ambiguous symptoms | ||
| ‘Poor memory’ | Often used as a shorthand for ‘cognitive problem’; does it mean episodic memory (events, routes, conversations, etc), semantic memory (words and concepts) or another domain of cognition? If the issue is with memory, is it with encoding information (attention), retaining new information (anterograde memory) or retrieving old information? | Any (may have poor episodic memory in dementia with Lewy bodies, frontotemporal dementia, etc, as well as Alzheimer’s disease*) |
| ‘Getting lost’ | Is this truly difficulty completing a route without assistance (topographical disorientation) or wandering (but ultimately getting there)? A useful question can be ‘how would you make your way home from here if you had to do it alone’? | Alzheimer’s disease (topography) and behavioural variant frontotemporal dementia (wandering) |
| ‘Word-finding difficulty’ | Often used as a shorthand for ‘language problem’; is it difficulty retrieving the name (very common), loss of vocabulary or difficulty pronouncing the word (uncommon)? | Alzheimer’s disease/others (retrieval), semantic primary progressive aphasia (vocabulary) and non-fluent primary progressive aphasia (articulation) |
| ‘Lost interest in reading’ | Is this a general loss of concentration or initiative, anhedonia, difficulty following the plot or a more specific problem tracking lines of text? | Alzheimer’s disease (multifactorial) and posterior cortical atrophy (text tracking) |
| ‘Doesn’t recognise people’ | Is this inability to recall their name (personal anomia, common) or to recognise faces or voices, ‘blanking’ familiar people? (true prosopagnosia or phonagnosia, uncommon) | Alzheimer’s/others (names), semantic primary progressive aphasia/right temporal lobe atrophy† (familiarity) |
| ‘More anxious/irritable’ | Might be psychiatric (eg, atypical depression) but also an early feature of many ‘organic’ dementias | Alzheimer’s disease, dementia with Lewy bodies, vascular and some frontotemporal dementias (eg, C9orf72 mutations) |
| ‘Black sheep of family’ | Youthful delinquency that contrasts with law-abiding siblings | Latent learning disability, very rarely genetic prion disease |
| Counterintuitive symptoms | ||
| ‘Asks meaning of words’ | Loss of ability to understand words in a familiar language | Semantic primary progressive aphasia |
| ‘Reads fine print but not the headlines’ | Visual apperceptive agnosia exposed by non-canonical (eg, very large or pixelated) text | Posterior cortical atrophy |
| ‘Can play tennis (etc) but can’t find ball on ground’ | Static visual localisation more impaired than motion vision (or occasionally the reverse), reflecting separable neuroanatomical substrates | Posterior cortical atrophy |
| ‘Says spouse is impostor’ | Misidentification delusion (Capgras, etc), can also be for location (eg, asks to go ‘home’ in own house) | Alzheimer’s disease, dementia with Lewy bodies |
| ‘Much nastier/nicer now’ | Altered interpersonal awareness and conduct | Behavioural variant frontotemporal dementia (nasty) and Alzheimer’s disease (nice) |
| ‘Become very musical/religious/punctual/good at Sudoku’ | Enhanced (sometimes loss of) interest/ability in abstract pursuits, usually with loss of interest/affection for other people, on a spectrum of alterations ranging from basic rewards (sweet food and sleep), through sense of humour and timekeeping, to puzzles/complex stimuli | Behavioural variant frontotemporal dementia and semantic primary progressive aphasia |
| Potentially misleading symptoms | ||
| ‘It all started after that…(accident/operation, etc)’ | Usually, this is attribution bias; occasionally we have seen cases where severe psychological trauma did seem to provoke catastrophic cognitive decline in a previously asymptomatic person | Any |
| ‘Distant memories are fine’ | Usually they are not, but highly overlearnt or emotional memories tend to become the focus of cherished anecdote | Alzheimer’s disease |
| ‘Poor short-term memory’ | To a neuropsychologist, this refers to the immediate span of working memory (up to ~30 s) but used colloquially to refer to recent episodic memory of variable span | Any |
| ‘Thinks people are stealing from them’ | Usually not a harbinger of psychosis but a specific delusion of theft (or infidelity) | Alzheimer’s disease, dementia with Lewy bodies |
| ‘Going deaf’ | Peripheral hearing should always be checked but in context may signify difficulty understanding word meaning | Semantic primary progressive aphasia |
| ‘Always been spiritual’ | Apparent receptivity to ‘ghosts’/presences may signify visual/extracampine hallucinations | Dementia with Lewy bodies |
| ‘Unexplained aches/pains’ | Hypochondriasis can occasionally reflect abnormal processing of interoceptive signals such as pain | Right temporal lobe atrophy and semantic primary progressive aphasia |
| Signs not to miss/misinterpret | ||
| Bottom apraxia | Difficulty orienting/positioning self in space as when sitting down in a chair | Posterior cortical atrophy and corticobasal syndrome |
| Closing in | Patients overlay their hand or drawing on examiner’s target—feature of organic apraxia | Alzheimer’s disease and posterior cortical atrophy |
| ‘(Vicar of) Dibley’ sign | Binary reversals during conversation—says ‘yes’ but means ‘no’, etc | Non-fluent primary progressive aphasia |
| Dysprosodia (isolated) | Most cases of ‘foreign accent syndrome’ (recognisable as such, sometimes simulated with pantomime exuberance) will be functional, but occasionally patients present with altered prosody and linguistic deficits only supervene (much) later | Non-fluent primary progressive aphasia |
| Executive dysfunction | As used, for example, in neuropsychological reports, it is not synonymous with ‘frontal lobe problem’ but reflects processing across distributed brain networks; moreover, patients with significant frontal lobe dysfunction (as reflected in abnormal behaviour) may perform well on executive tests | Any |
| Head-turning | To accompanying person, during history taking—lack of confidence/retained awareness of problem/poor memory | Alzheimer’s disease |
| Perioral dyskinesias | Subtle trembling movements of lips/lower face | Alzheimer’s disease (younger onset) |
| Pigeon sign | Turns head this way and that, trying to make sense of a picture or visual array | Posterior cortical atrophy |
| Repetitiveness conversing | Signifies an organic problem with anterograde episodic memory/accelerated forgetting | Alzheimer’s disease |
| Semantic paraphasias | Substitution of related words on a naming task usually will not reflect a primary semantic problem but more likely anomia (impaired word retrieval) with attempted compensation | Alzheimer’s disease, others |
| Surface dyslexia | Sounds irregularly pronounced words as they are printed, due to loss of vocabulary-based reading | Semantic primary progressive aphasia |
| ‘Thousand yard stare’ | Sense of unease/threat conveyed by patient who lacks normal social facial microreactivity | Right temporal lobe atrophy |
| Tie sign | Patient touches examiner’s tie/face when trying to locate their outstretched hand, due to visuospatial disorientation | Posterior cortical atrophy |
| ‘Variable deficit’ | Apraxia is intrinsically variable; organic cognitive impairment of any cause can be impacted by stress or fatigue, and certain entities are characterised by marked fluctuation‡ (sometimes sleep benefit/deterioration), due to seizures, channel dysfunction or impaired dopaminergic/cholinergic switching between brain states | Dementia with Lewy bodies (sleep benefit), transient epileptic amnesia (sleep deterioration), inflammatory, immune |
*Refers to the clinical syndrome of typical (memory-led) Alzheimer’s disease.
†Refers to the syndrome associated with right temporal lobe atrophy, within the behavioural variant frontotemporal dementia spectrum.
‡Not the same as inconsistency—organic cognitive fluctuations are internally consistent.