Patients with subjective cognitive failures have lower hippocampal volume, according to a study in the October 7 Neurology. This association was observed even in persons without objective cognitive impairment and independent of white matter lesions.
As part of the Radboud University Nijmegen Diffusion Tensor and MRI Cohort study, A.G.W. van Norden, MD, and colleagues prospectively collected data on 503 patients ages 50 to 85 who visited the neurology outpatient clinic and underwent routine diagnostic brain imaging for reasons not related to cognitive and motor study outcome.
Defining Subjective Cognitive Failures
All participants underwent fluid attenuated inversion recovery and T1-weighted MRI scanning. Subjective cognitive failures, which were assessed with use of a 15-item semistructured interview based on the Cognitive Failure Questionnaire, were considered present when a person reported at least one moderate problem (score, 2 or higher) on an item having a score range of 0 to 3 or a score of 1 on dichotomous items, noted Dr. van Norden, a resident in the Department of Neurology, Radboud University Nijmegen Medical Centre, the Netherlands, and coauthors. Subjective cognitive failures were subdivided into subjective memory failures and subjective executive failures; subjective memory failures were present if failures were reported in one of the 10 items concerning memory problems, and subjective executive failures were defined as failures in planning, concentration, and slowness in thought.
Cognitive Failures Linked to Older Age, Depression
According to the researchers, persons who reported subjective cognitive failures were older and had more depressive symptoms, after adjustment for age and gender. Subjective cognitive, memory, and executive failures were all associated with reduced objective performance, independent of depressive symptoms, white matter lesions, and hippocampal volume.
Patients with subjective cognitive, memory, and executive failures also had lower hippocampal volume, compared with those who did not have these impairments. No relationship was found between subjective cognitive failures and white matter lesion volume, except for participants reporting subjective executive failures.
Decreasing hippocampal volume was related to increasing severity of subjective cognitive, memory, and executive failures. When severe, moderate, and no subjective cognitive failures were assessed, the difference in hippocampal volume was most apparent in subjects with good cognitive performance. This relationship was also found for subjective memory function, with borderline significance for subjects with moderate memory performance. Adjustment for white matter lesions did not change the magnitude of these associations, said Dr. van Norden’s group. Furthermore, white matter lesion volume was not related to severity of disease in the objective cognitive strata or in the whole group analysis. “Progression of failures was not associated with hippocampal volume, nor with white matter lesion volume,” they observed.
“Importantly, the relation between lower hippocampal volume and subjective cognitive failures and subjective memory failures was demonstrated in subjects with good objective performance,” Dr. van Norden and colleagues stressed. “This may provide an underlying pathoanatomic explanation for the frequently observed subjective cognitive failures and may therefore function as an early marker for the development of diseases characterized by memory loss, including Alzheimer’s disease and its attendant neuropathologic substrates such as hippocampal atrophy.”
—Marguerite Spellman