Stable symptoms over three years, normal cognitive test performance with marked intra-test variability, negative amyloid imaging and normal hippocampal volumes together exclude prodromal Alzheimer disease and support a positive diagnosis of functional cognitive disorder. The clinical picture is completed by the anxiety-driven hypervigilance, the repeated checking and the social withdrawal, which are perpetuating factors rather than consequences of a degenerative process.
The mechanism to convey is attentional. Memory retrieval and everyday task performance are largely automatic; directing sustained conscious attention onto them and monitoring for failure disrupts the automatic processes and generates the very errors the patient fears, which reinforces the belief and the monitoring in a self-perpetuating loop. Treatment therefore aims at reducing symptom monitoring and checking, treating anxiety with cognitive behavioural approaches, restoring social activity, correcting sleep and reviewing sedating or anticholinergic medication. Functional cognitive disorder has been described as the blind spot of dementia services, and giving it a name reduces repeated investigation.
On the ABPN blueprint this maps to the Clinical aspects of neurologic disease axis, because the competency is placing a clinical syndrome correctly within the differential diagnosis of cognitive complaints. Note that functional cognitive disorder can coexist with early degenerative disease, so worsening or newly objective deficits warrant reassessment.
Incorrect Answers
- A. A negative amyloid scan with normal hippocampal volumes and stable performance over three years argues strongly against prodromal Alzheimer disease; repeating imaging reinforces illness beliefs.
- B. A purely negative explanation leaves the patient without a framework, and is associated with continued health-seeking and worse outcome.
- D. Cholinesterase inhibitors are indicated for established Alzheimer disease and have no role in functional cognitive disorder.
- E. Mild cognitive impairment requires objective impairment on testing, which is absent here; the label would compound her anxiety.
Testing Pearls
- Stable symptoms with normal testing over years argue against neurodegeneration.
- Excessive conscious monitoring of automatic cognitive processes generates real errors.
- Treatment targets checking behaviour, anxiety, sleep and sedating medication.
- A positive diagnostic label reduces repeated and costly investigation.
- Functional cognitive disorder may coexist with early degenerative disease, so review progression.
References
- Jankovic J, Mazziotta JC, Newman NJ, Pomeroy SL, editors. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022. p. 2085-2086.
- Ball HA, McWhirter L, Ballard C, Bhome R, Blackburn DJ, Edwards MJ, et al. Functional cognitive disorder: dementia's blind spot. Brain. 2020;143(10):2895-2903.
- Espay AJ, Aybek S, Carson A, Edwards MJ, Goldstein LH, Hallett M, et al. Current concepts in diagnosis and treatment of functional neurological disorders. JAMA Neurol. 2018;75(9):1132-1141.
