Functional cognitive disorder in subjective cognitive decline-A 10-year follow-up

In memory clinics, patients with significant memory complaints without objective neuropsychological findings are common. They are classified as subjective cognitive decline (SCD) and, as a group, face a heightened risk for future dementia. However, the SCD group is heterogeneous and comprises patients suffering from a somatoform condition, namely functional cognitive disorder (FCD). These patients make up at least 11% of memory clinics' attendees. The aim of this long-term follow-up study was to investigate if patients diagnosed with FCD also face a higher risk of developing dementia.

Forty-two Patients were recruited at a university hospital memory clinic. FCD was diagnosed according to the Schmidtke criteria (see Table 1). Ten years later, all were invited again. Participants were interviewed, screened for depression and given neuropsychological tests of verbal memory and information processing speed. Cognitive impairment was defined as performance below 1.5 standard deviations (SD) of the age-related mean.

Twenty-eight of 42 patients (67%) took part in this follow-up. The group's mean results in both cognitive measures were stable over time. All individual performances were within 1.5 SD. With 10 patients (24%), brief contact was successful and manifest dementia could be excluded. Four patients (10%) could not be contacted.

In retrospect, the Schmidtke criteria for FCD safely identified memory clinic attendees with SCD who did not proceed to Mild Cognitive Impairment or dementia. None of the patients who could be contacted for this follow-up after a decade (90% of baseline participants) showed signs of dementia.