Continuous vs. intermittent neurofeedback to regulate auditory cortex activity of tinnitus patients using real-time fMRI - A pilot study

Abstract

The emerging technique of real-time fMRI neurofeedback trains individuals to regulate their own brain activity via feedback from an fMRI measure of neural activity. Optimum feedback presentation has yet to be determined, particularly when working with clinical populations. To this end, we compared continuous against intermittent feedback in subjects with tinnitus.Fourteen participants with tinnitus completed the whole experiment consisting of nine runs (3 runs × 3 days). Prior to the neurofeedback, the target region was localized within the auditory cortex using auditory stimulation (1 kHz tone pulsating at 6 Hz) in an ON-OFF block design. During neurofeedback runs, participants received either continuous (n = 7, age 46.84 ± 12.01, Tinnitus Functional Index (TFI) 49.43 ± 15.70) or intermittent feedback (only after the regulation block) (n = 7, age 47.42 ± 12.39, TFI 49.82 ± 20.28). Participants were asked to decrease auditory cortex activity that was presented to them by a moving bar. In the first and the last session, participants also underwent arterial spin labeling (ASL) and resting-state fMRI imaging. We assessed tinnitus severity using the TFI questionnaire before all sessions, directly after all sessions and six weeks after all sessions. We then compared neuroimaging results from neurofeedback using a general linear model (GLM) and region-of-interest analysis as well as behavior measures employing a repeated-measures ANOVA. In addition, we looked at the seed-based connectivity of the auditory cortex using resting-state data and the cerebral blood flow using ASL data.GLM group analysis revealed that a considerable part of the target region within the auditory cortex was significantly deactivated during neurofeedback. When comparing continuous and intermittent feedback groups, the continuous group showed a stronger deactivation of parts of the target region, specifically the secondary auditory cortex. This result was confirmed in the region-of-interest analysis that showed a significant down-regulation effect for the continuous but not the intermittent group. Additionally, continuous feedback led to a slightly stronger effect over time while intermittent feedback showed best results in the first session. Behaviorally, there was no significant effect on the total TFI score, though on a descriptive level TFI scores tended to decrease after all sessions and in the six weeks follow up in the continuous group. Seed-based connectivity with a fixed-effects analysis revealed that functional connectivity increased over sessions in the posterior cingulate cortex, premotor area and part of the insula when looking at all patients while cerebral blood flow did not change significantly over time.Overall, these results show that continuous feedback is suitable for long-term neurofeedback experiments while intermittent feedback presentation promises good results for single session experiments when using the auditory cortex as a target region. In particular, the down-regulation effect is more pronounced in the secondary audi...

Advances in fMRI Real-Time Neurofeedback

“…There are in general two ways regarding how often feedback scores are presented during the fMRI neurofeedback training; continuously and intermittently [50–52]. Here, continuous feedback refers to the feedback that is presented continuously during the neurofeedback training, and the feedback score changes every time the brain activation is measured by fMRI, for instance, every 2 sec.…”

“…Intermittent feedback is defined as the feedback provided not continuously, and provided only once in a while, for instance, at the end of a block that spans 40 sec. The intermittent feedback score is based on the brain activation averaged across the block, which includes several fMRI measurements [50,51]. It is controversial which type of feedback is more effective.…”

Learning 2-in-1: Towards Integrated EEG-fMRI-Neurofeedback

“…However its effective deployment in the clinical practice is being held back by the debated evidence about its efficiency, most likely as a result of poor study design and lack of established guidelines and knowledge about the underlying mechanisms of NF (Thibault et al, 2016;Perronnet et al, 2016). In recent years, increasingly rigorous approaches are becoming the new standard (Ros et al, 2019;Sulzer et al, 2013;Stoeckel et al, 2014;Thibault et al, 2016), and new studies are digging into the mechanisms Sitaram et al, 2016;Emmert et al, 2016;Birbaumer et al, 2013;Kober et al, 2013) as well as the methodological aspects of NF (Sorger et al, 2019;Emmert et al, 2017;Krause et al, 2017;Sorger et al, 2016;Sepulveda et al, 2016). However another reason for the debated efficiency of current approaches might be the inherent limitations of single imaging modalities (Biessmann et al, 2011;Fazli et al, 2015).…”

Real-time functional magnetic resonance imaging in obsessive-compulsive disorder

“…Recent reviews49 highlight that rtfMRI is effective in regulating several cortical and subcortical regions (eg, amygdala, anterior insula, IFG, ACC, superior temporal gyrus, and a diversity of sensorimotor regions), impacting multiple psychological processes (eg, affective states,50 evaluation of emotional visual stimuli, auditory attention, or language) and improving several clinical conditions (eg, tinnitus,51 nicotine dependence,52 depression,53 psychpathy54). Even when aimed at specific brain regions, the effects of rtfMRI are mediated by changes in extended brain network systems 55.…”