Three-Year Reliability of MEG Visual and Somatosensory Responses

Abstract

A major goal of many translational neuroimaging studies is the identification of biomarkers of disease. However, a prerequisite for any such biomarker is robust reliability, which for magnetoencephalography (MEG) and many other imaging modalities has not been established. In this study, we examined the reliability of visual (Experiment 1) and somatosensory gating (Experiment 2) responses in 19 healthy adults who repeated these experiments for three visits spaced 18 months apart. Visual oscillatory and somatosensory oscillatory and evoked responses were imaged, and intraclass correlation coefficients (ICC) were computed to examine the long-term reliability of these responses. In Experiment 1, ICCs showed good reliability for visual theta and alpha responses in occipital cortices, but poor reliability for gamma responses. In Experiment 2, the time series of somatosensory gamma and evoked responses in the contralateral somatosensory cortex showed good reliability. Finally, analyses of spontaneous baseline activity indicated excellent reliability for occipital alpha, moderate reliability for occipital theta, and poor reliability for visual/somatosensory gamma activity. Overall, MEG responses to visual and somatosensory stimuli show a high degree of reliability across 3 years and therefore may be stable indicators of sensory processing long term and thereby of potential interest as biomarkers of disease.

Stimulus-induced narrowband gamma oscillations are test-retest reliable in healthy elderly in human EEG

“…In our study, relative power (ICC(1) = 0.81) measures were more reliable than absolute power (ICC(1) = 0.76) in the alpha band, within the stimulus period. Moreover, in line with the study by McCusker and colleagues (2021), the resting state alpha reliability of both the relative power (ICC(1) = 0.83) and absolute power (ICC(1) = 0.78) were higher than the stimulus period. Apart from alpha power, alpha peak frequency also has been investigated and found to be test-retest reliable (Maltez et al, 2004; Näpflin et al, 2007, 2008; Grandy et al, 2013).…”

“…Hence, the low ICC in our case could be due to multiple reasons, such as the stimulus, recording modality and the test-retest period. Test-retest interval seems to be an important factor, since McCusker and colleagues (2021) who studied induced gamma in MEG after a period of up to 3 years reported much lower agreement ICC(A,1) of 0.55 (McCusker et al, 2021). Apart from the duration, the lower values could be due to the ICC type used, as the agreement type ICCs are usually lower than the consistency and classical definitions in presence of systematic bias in the data (although we did not find this in our data).…”

“…Several studies have compared absolute versus relative power (percentage value of power within the band w.r.t total power across all the bands), with mixed results. Some studies found relative alpha power to be more reliable than absolute power (John et al, 1983; Kondacs and Szabó, 1999), others found comparable reliability (Gasser et al, 1985; Salinsky et al, 1991), while a recent study (McCusker et al, 2021) reported more robust reliability of absolute alpha activity in resting state than in the stimulus period (alpha desynchronization). In our study, relative power (ICC(1) = 0.81) measures were more reliable than absolute power (ICC(1) = 0.76) in the alpha band, within the stimulus period.…”

“…The only EEG study to our knowledge that reported induced gamma oscillations used a checkerboard stimulus that mainly induced broadband gamma (Keil et al, 2003); another study that used gratings to induce gamma oscillations reported reliability of evoked, not induced, gamma oscillations (Fründ et al, 2007). Second, although having a test-retest interval of a year allows for checking its feasibility as an annual check-up, most of these studies have tested reliability with test-retest interval spanning from a few weeks to months (but see McCusker et al, 2021 who had a test-retest interval of 3 years, although they used checkerboard patterns and their paradigm also included a behavioural task). Third, most studies have been conducted on young subjects (20-40 years).…”

Three-year reliability of MEG resting-state oscillatory power

“…Test-retest reliability in functional neuroimaging remains a timely and important topic across multiple modalities, including fMRI, EEG, and MEG ( Elliott et al, 2020 ; McCusker et al, 2020 ; McEvoy et al, 2000 ). As defined by Elliot et al (2020) , test-retest reliability refers to the reproducibility of results from a given measure under nearly equivalent conditions.…”