Multimodal Assessment of Neural Substrates in Computerized Cognitive Training: A Preliminary Study

Abstract

Background and purpose: Several studies have validated the clinical efficacy of computerized cognitive training applications. However, few studies have investigated the neural substrates of these training applications using simultaneous multimodal neuroimaging modalities. We aimed to determine the effectiveness of computerized cognitive training and corresponding neural substrates through a multimodal approach.

Methods: Ten patients with mild cognitive impairment (MCI), six patients with subjective memory impairment (SMI), and 10 normal controls received custom-developed computerized cognitive training in the memory clinic of a university hospital. All of the participants completed 24 sessions of computerized cognitive training, each lasting 40 minutes and performed twice weekly. They were assessed using neuropsychological tests (both computerized and conventional), electroencephalography, fluorodeoxyglucose positron-emission tomography (FDG-PET), volumetric magnetic resonance imaging (MRI), and diffusion-tensor imaging (DTI) at pre- and posttraining.

Results: The patients with MCI exhibited significant improvements in the trail-making test-black & white-B, and memory domain of the computerized cognitive assessment. Subjects with normal cognition exhibited significant improvements in scores in the language and attention-/psychomotor-speed domains. There were no significant changes in subjects with SMI. In the pre- and posttraining evaluations of the MCI group, FDG-PET showed focal activation in the left anterior insula and anterior cingulate after training. Volumetric MRI showed a focal increase in the cortical thickness in the rostral anterior cingulate. DTI revealed increased fractional anisotropy in several regions, including the anterior cingulate.

Conclusions: The anterior cingulate and anterior insula, which are parts of the salience network, may be substrates for the improvements in cognitive function induced by computerized cognitive training.

Keywords: cingulate; computerized cognitive training; insula; magnetic resonance imaging; mild cognitive impairment; salience network.

Fig. 1. Statistical parametric mapping analysis of pre- and posttraining fluorodeoxyglucose positron-emission tomography in the mild cognitive impairment group. Focal activation was observed in the left anterior insula, anterior cingulate cortex, and right lateral temporal cortex (uncorrected p<0.001).

Fig. 2. Surface-based morphometry of pre- and posttraining volumetric magnetic resonance imaging scans in the mild cognitive impairment group. A focal increase in cortical thickness was detected in the rostral anterior cingulate cortex.

Fig. 3. Tract-based spatial statistics analysis of pre- and posttraining diffusion-tensor imaging in the mild cognitive impairment group. There were several regions with increased fractional anisotropy (shown in red), including the anterior and posterior cingulate cortices.