Gamma oscillations predict pro-cognitive and clinical response to auditory-based cognitive training in schizophrenia

Abstract

Cognitive impairments are pervasive and disabling features of schizophrenia. Targeted cognitive training (TCT) is a “bottom-up” cognitive remediation intervention with efficacy for neurocognitive outcomes in schizophrenia, yet individual responses are variable. Gamma oscillatory measures are leading candidate biomarkers in the development of biologically informed pro-cognitive therapeutics. Forty-two schizophrenia patients were recruited from a long-term residential treatment facility. Participants were randomized to receive either 1 h of cognitive training (TCT, n = 21) or computer games (TAU, n = 21). All participants received standard-of-care treatment; the TCT group additionally completed 30 h of cognitive training. The auditory steady-state response paradigm was used to elicit gamma oscillatory power and synchrony during electroencephalogram recordings. Detailed clinical and cognitive assessments were collected at baseline and after completion of the study. Baseline gamma power predicted cognitive gains after a full course of TCT (MCCB, R2 = 0.31). A change in gamma power after 1-h TCT exposure predicted improvement in both positive (SAPS, R2 = 0.40) and negative (SANS, R2 = 0.30) symptoms. These relationships were not observed in the TAU group (MCCB, SAPS, and SANS, all R2 < 0.06). The results indicate that the capacity to support gamma oscillations, as well as the plasticity of the underlying ASSR circuitry after acute exposure to 1 h of TCT, reflect neural mechanisms underlying the efficacy of TCT, and may be used to predict individualized treatment outcomes. These findings suggest that gamma oscillatory biomarkers applied within the context of experimental medicine designs can be used to personalize individual treatment options for pro-cognitive interventions in patients with schizophrenia.

Individual Resonant Frequencies at Low-Gamma Range and Cognitive Processing Speed

“…However, as shown by the lack of association between IGFs and processing speed in our sample, it is possible that connection can be observed in clinical populations with clearly impaired cognitive processing, or be highly modality-specific (i.e., auditory response is associated to the performance of auditory tasks). The latter assumption connects with a recent suggestion of Molina et al [ 66 ] that evoked gamma may be an index of the brain’s overall “adaptive integrity“ of the lower-level perceptual networks. We tested healthy young participants, and all tasks utilized in the current research were based on visual domain assessment.…”

Mindfulness Training Alters Resting-State EEG Dynamics in Novice Practitioners via Mindful Breathing and Body-scan

“…The results of mindfulness practice were rather similar to the EEG findings on beta and gamma neurofeedback training (a training aimed at improving beta or gamma power) that showed that 10 days of beta and gamma neurofeedback training led to improved episodic memory among healthy adults (Keizer, Verschoor, Verment, & Hommel, 2010). A similar association between long-term cognitive training and gamma power elevation was also found among the elderly population (Staufenbiel, Brouwer, Keizer, & Van Wouwe, 2014) and patients with Alzheimer's disease (Van Deursen, Vuurman, Verhey, Van Kranen-Mastenbroek, & Riedel, 2008), schizophrenia (Molina et al, 2020), and attention-deficit/hyperactivity disorder (Yordanova, Banaschewski, Kolev, Woerner, & Rothenberger, 2001). Furthermore, the results were consistent with the neuroimaging findings that highly focused participants with 6 weeks of mindfulness training showed better cognitive performance in the Stroop test, in addition to exhibiting higher dlPFC activation (M. Allen et al, 2012).…”

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“…However, this is not completely surprising, since also previous research found that greater service intensity is related to higher rates of improvement in neurocognition and global functioning over time. 61–63 …”