An approach to cognitive symptoms in younger people Dr Jeremy Isaacs Consultant Neurologist and Dementia Clinical Lead St George s Hospital Excellence in specialist and community healthcare
I m worried about my memory Awareness and fear of dementia in the population is increasing Public health campaigns have not distinguished between benign and non-benign memory symptoms This is generating a lot of worried well people
Dementia is rare in younger people Incidence of dementia in 45-64 age group 11.5 cases per 100,000 person-years Alzheimer s disease 4.2 Frontotemporal dementia 3.5 Huntington s disease 0.8 Extrapolated across England and Wales 460 new cases of FTD and 550 new cases of Alzheimer s each year Mercy et al, Neurology 2008
Functional cognitive disorders Subjective cognitive symptoms in the absence of brain pathology Commonest cause of cognitive symptoms in people aged <65 Has distinctive features that allow a positive diagnosis to be made Important not to miss features that point towards a organic cognitive disorder
Epidemiology of functional cognitive symptoms Cognitive Symptom Frequency Reported in Community Controls: n=223, mean age 30 Forgets recent telephone conversation 9% Forgets why they entered room 27% Forget yesterday s breakfast 27% Forgets where car was parked 32% Loses car keys 31% Forgets where they went today 5% Forgets appointment dates 20% Loses items around house 17% Concentration difficulty 14% McCaffrey RJ, Bauer L, Palav AA, O Bryant S (2006). Practitioner s guide to symptom base rates in the general population, Springer Science, & Business Media.
College Students: n=620, age range 17 26 Memory Gaps 10% Speech problems 17% Word finding lapses 27% Unrecalled behaviour 9% McCaffrey RJ, Bauer L, Palav AA, O Bryant S (2006). Practitioner s guide to symptom base rates in the general population, Springer Science, & Business Media.
Types of functional cognitive complaint Lapses of attention or concentration I went upstairs/into a room/opened the fridge door and forgot why These experiences are not due to memory loss They happen because we have evolved not to encode everything that s in our short-term memory Minor memory or word retrieval difficulties I can t remember people s names I couldn t think of the word for They happen because of physiological inefficiencies in word retrieval In FCD, attention is shifted towards these physiological cognitive lapses Patients become hypervigilant to what are normal experiences Which may be followed by a catastrophic interpretation i.e. that something must be wrong
Classification of functional cognitive disorder 1. Isolated functional cognitive disorder - Including following specific triggers e.g. mild TBI - With or without dementia-related health anxiety 2. Functional cognitive symptoms associated with mood disorder 3. FCD in association with another functional disorder e.g. chronic fatigue syndrome, fibromyalgia Adapted from Stone et al. Journal of Alzheimer s Disease 48 (2015) S5 S17
Approach to the functional cognitive patient As in any functional disorder, hallmark is incongruity between the patient s subjective experience of bodily function and what is objectively demonstrable Look for inconsistencies between subjective burden of symptoms and objective everyday functioning Patient holding down high powered job or complex family commitments despite high burden of cognitive symptoms Patient reporting poor memory who describes memory lapses in exquisite detail Patient is convinced of a problem but partner and others haven t expressed concern Determine whether the predominant issue is the consequence of cognitive lapses or the patient s emotional response to them
Predisposing Precipitating Perpetuating Perfectionist expectations of cognitive performance Stressful life event Depression Subjectively impaired metamemory Physical illness including mild TBI & chemotherapy Hypervigilance to cognitive lapses Early life trauma Major psychiatric illness Catastrophic interpretation of cognitive lapses Other functional disorders e.g. CFS, fibromyalgia Parent developing dementia Specific dementia-related health anxiety Chronic pain Ongoing stress Tendency to dissociate Health anxiety
Examination Brief cognitive instruments have limited value in younger patients with mild cognitive symptoms where the differential diagnosis is FCD vs a prodromal dementia Too insensitive to pick up subtle impairments, especially in well educated subjects (false negative) Not designed to detect non-ad dementias (false negative) Many patients with FCD will lose marks due to poor effort (false positive) Better to observe patient s speech for features of normal cognition Richly detailed history with multiple examples of cognitive lapses History in which events are precisely located in time Patient s ability to reference an earlier part of the consultation Absence of word finding pauses
Treatment Explanation and reassurance Introduce concept of functional cognitive symptoms Almost always accepted by patients Provide feedback on how their ability to give a detailed history is a sign of normal memory function e.g. your memory works fine when you aren t focussing on it In mild cases normalisation of symptoms might be sufficient If any suggestion of depression, discuss treatment options with patient Encourage graded return to normal utilisation of memory CBT targeted to cognitive symptoms possible in experienced hands, but unproven
When to be concerned The commonest organic cause of memory loss in people aged > 50 is Alzheimer s disease Initial symptoms are insidious and are rarely noticed first by the patient Typical examples are witnessed lapses in episodic and prospective memory Forgetting a phone conversation Asking the same question repeatedly Forgetting a plan that was made a few days ago
Other dementia syndromes seen in younger people Behavioural variant frontotemporal dementia Patient will be brought by a concerned partner or supporter Who will be much more concerned about the symptoms than the patient Primary progressive aphasia Word finding difficulties will be apparent to an informant And to a non-specialist unless it s a very early logopenic aphasia If necessary test verbal fluency, single word and sentence repetition, confrontational naming, picture description and definitions
Other dementia syndromes seen in younger people Posterior cortical atrophy May report visual problems initially Informant might describe driving errors e.g. erratic vehicle placement, veering to one side Proprioceptive or praxis deficits e.g. difficulty typing Alcohol-related dementia Patient can be any age Predominant deficits are frontal May overlap with Korsakoff syndrome
When to be concerned about dementia in a younger person Patient is over 50 History of alcohol misuse Spouse/relative/friend brings patient in They do most of the talking Patient less aware of problems than informant Objective decline in function e.g. work performance A concerned informant is more important than a brief cognitive test
Summary Subjective cognitive symptoms are very common in the population People who present are different from the background population They have specific predisposing, precipitating and perpetuating characteristics Memory perfectionism Stress Depression Dementia-related health anxiety
Functional cognitive disorder A positive diagnosis should be possible based on patient profile and symptoms, including incongruities, exactly as in other FDs Likely that offering a sympathetic explanation and reassurance, treating depression and targeted CBT will help But further research on treatment is needed
Summary Brief cognitive instruments lack sensitivity and specificity where the differential diagnosis is FCD versus a prodromal dementia And have particularly poor predictive value in younger cohorts where the prevalence of prodromal dementia is very low and non-alzheimer dementias are a larger proportion Significantly more value from Looking for positive features of FCD Indirectly examining patient s cognition via their spontaneous speech Taking an informant history focussed on features of the commoner causes of organic cognitive impairment in younger people (AD, bvftd, PPA, PCA, alcohol)
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