Subjective Complaints are Similar in Subjective Cognitive Decline and Early-Stage Alzheimer's Disease when Assessed in a Memory Clinic Setting.

BACKGROUND: Subjective cognitive complaints are generally poorly associated with objective memory functioning in older persons. Subjective cognitive decline (SCD) is a key feature in SCD and amnestic mild cognitive impairment (aMCI) which both can represent early Alzheimer's disease (AD). The aim of this study was to assess how memory clinic patients with SCD, MCI and mild AD dementia scored on 3 different complaint measures and if the format of assessment had an impact on the association with cognitive functioning, age, and depressive symptoms. METHODS: We included 17 SCD patients, 17 aMCI patients, 17 patients with mild AD, and 30 controls. Complaints were assessed with the Cognitive Change Index (CCI), the Subjective Memory Complaints (SMC) scale, and the Memory Complaint Questionnaire (MAC-Q). RESULTS: There were no significant differences between the total scores in the patient groups on the questionnaires. However, significant differences were found in the number of patients classified with impairment when using the CCI, the SMC, and the MAC-Q. Scores on all questionnaires were significantly associated with depressive symptoms, and significant associations with age, gender, and Addenbrookes Cognitive Examination score were found for the SMC. In patients with cognitive dysfunction, lower memory awareness significantly predicted fewer cognitive complaints. CONCLUSIONS: SCD patients in a memory clinic setting report the same degree of cognitive impairment as patients with aMCI and mild dementia, and in a hospital-based cohort we extend previous findings from healthy controls, that definition of SCD may depend on the format of assessment.

Impairment of Episodic-Specific Autobiographical Memory in Individuals with Subjective Cognitive Decline and in Patients with Prodromal or Mild Alzheimer's Disease.

BACKGROUND: Autobiographical memory (AM) is a personal form of memory that becomes impaired in the early, clinical stages of Alzheimer's disease (AD). In the "preclinical" phase of AD, neuropathological hallmarks are present (especially in a brain network underpinning AM), but performance on standardized neuropsychological tests is normal. Even so, some patients have subjective cognitive decline (SCD). OBJECTIVE: The aim was to 1) investigate AM performance on two tests with different approaches in SCD, and in prodromal and mild AD, and 2) examine the association between the AM tests. METHODS: We included 17 SCD patients with heightened risk of AD, 17 amnestic mild cognitive impairment (aMCI) patients, 17 patients with mild dementia due to AD, and 30 healthy controls. Patients were diagnosed according to international criteria, and all participants had MMSE scores≥24. AM was assessed using the Columbia Autobiographical Memory Interview-Short Form (CAMI-SF) and the Three Events Test. These tests measure the production of contextual details. RESULTS: Significant group effects were found for the Three Events Test and the CAMI-SF. All patient groups produced significantly fewer contextual details than the controls on the Three Events Test. On CAMI-SF, the aMCI and mild AD groups were able to answer fewer questions or gave significantly less detailed answers than the other groups. The SCD patients performed below the controls on CAMI-SF, but the difference was not significant. CONCLUSION: AM may be impaired in very early AD, even in the phases where standardized episodic memory tests show no decline.