Fig 1.
Mean (SD) of hearing thresholds in participants with tinnitus and controls.
Table 1.
Participant demographics.
Fig 2.
Sixteen sources (red circles) and 16 detectors (grey circles) forming channels were placed on frontal, temporal and occipital regions of the scalp. Channel numbers are shown. 36 long and 4 short channels (marked by * and yellow source-detector links) were formed.
Fig 3.
fNIRS experiment block design.
Three recordings were performed during each testing session with 3–5 minute rest breaks in-between. In ‘recording period 2’, six 15-second auditory and six 15- second visual stimuli were applied. A 3–5 minute break was then given to participants and then ‘recording period 3’ was performed to collect a further four auditory and four visual trials. All together, 10 trials of each stimulus type were collected. Stimuli were randomised across blocks with no more than two stimuli of the same type in a row. Non-stimulus intervals between stimuli within a recording period were 20 or 25 seconds long. NSI: non-stimulus interval.
Table 2.
Anatomical region associated with each channel number.
Fig 4.
Hbo and HbR-derived whitened Correlations (measure of connectivity) between left and right seeds with frontal and occipital channels.
Mean and SEM of correlations between seeds and channels in each region are shown. * p < 0.05.
Fig 5.
Group averaged auditory responses recorded from channels over the left and right temporal cortex.
HbO (A) and HbR (B) responses shown. Channel numbers are shown above plots. Vertical lines show stimulus onset and offset times at 0 and 15 seconds.
Fig 6.
Group averaged visual responses recorded from occipital channels over the cuneus and superior occipital gyrus.
HbO (A) and HbR (B) responses shown. Channel numbers are shown above plots. Vertical lines show stimulus onset and offset times at 0 and 15 seconds.
Fig 7.
Group averaged auditory and visual responses.
HbO (A) and HbR (B) responses averaged over auditory and visual ROIs. ROI: region of interest.
Fig 8.
Change in connectivity with duration of tinnitus and loudness.
(A) Change in HbO derived temporal- frontal connectivity with duration of tinnitus. (B) Change in HbR derived temporal- occipital connectivity with subjective ratings of loudness.
Table 3.
Classifiers and features with highest accuracy for predicting participants with tinnitus and controls.
Table 4.
Classifiers and features with highest accuracy for predicting severity of tinnitus (slight/ mild n = 18, versus moderate/ severe n = 7) as rated using the Tinnitus Handicap Inventory (THI).