Activation and Effective Connectivity Changes Following Explicit-Memory Training for Face–Name Pairs in Patients With Mild Cognitive Impairment

Abstract

Background Mild cognitive impairment (MCI) is often a precursor to Alzheimer’s disease. Little research has examined the efficacy of cognitive rehabilitation in patients with MCI, and the relevant neural mechanisms have not been explored. We previously reported on a pilot study showing the behavioral efficacy of cognitive rehabilitation using mnemonic strategies for face-name associations in patients with MCI. Here we used functional magnetic resonance imaging (fMRI) to test whether there were training-specific changes in activation and connectivity within memory-related areas. Methods Six patients with amnestic, multi-domain MCI underwent pre- and post-training fMRI scans, during which they encoded 90 novel face-name pairs, and completed a 4-choice recognition memory test immediately after scanning. Patients were taught mnemonic strategies for half the face-name pairs during three intervening training sessions. Results Training-specific effects comprised significantly increased activation within a widespread cerebral cortical network involving medial frontal, parietal, and occipital regions, the left frontal operculum and angular gyrus, and regions in left lateral temporal cortex. Increased activation common to trained and untrained stimuli was found in a separate network involving inferior frontal, lateral parietal and occipital cortical regions. Effective connectivity analysis using multivariate, correlation-purged Granger causality analysis revealed generally increased connectivity after training, particularly involving the middle temporal gyrus and foci in the occipital cortex and the precuneus. Conclusion Our findings suggest that the effectiveness of explicit memory training in patients with MCI is associated with training-specific increases in activation and connectivity in a distributed neural system that includes areas involved in explicit memory.

Cognitive Rehabilitation of Memory for Mild Cognitive Impairment: A Methodological Review and Model for Future Research

“…regions (Hampstead, Stringer, Stilla, Deshpande, et al, 2011) as well as a partial restoration of hippocampal activation in those with MCI (Hampstead, Stringer Stilla, Giddens, & Sathian, 2012). Belleville and colleagues (2011) also suggested that the right temporoparietal junction may play a compensatory role during strategy use in MCI patients.…”

Non-pharmacological intervention for memory decline

“…In a study conducted by Hampstead et al (2011), fMRI was used to test whether there were training-specific changes in the activation and connectivity within memory-related areas of patients with multidomain MCI. The findings suggested that the effectiveness of explicit memory strategy training in subjects with MCI (associative memory) is associated with training-specific increases in activation and connectivity across a distributed neural system, which included areas involved in explicit memory function.…”

Multistimulation Group Therapy in Alzheimer’s Disease Promotes Changes in Brain Functioning

“…Hence, some authors have proposed modified versions such as biopsycosocial or psychobiosocial therapies. 2,3 Functional magnetic resonance imaging (fMRI), due to its capacity to monitor neural circuits reorganization, has been recently introduced to evaluate the efficacy of these nonpharmacological treatments (see Cramer et al 4 for a review), also including treatments for amnestic mild cognitive impairment (MCI) 5 and AD. 6 Cognitive stimulation (CS) is probably the most widespread and well-studied technique in this field, but it is still a matter of debate whether this therapy is able to slow down the disease course.…”