Variation in Uncomfortable Loudness Levels (ULLs)
across frequency: A marker of misophonia and severe hyperacusis
Across-frequency variations in ULLs have not
been fully explored in the past studies. Most researchers reported that ULLs
averaged across participants did not change markedly across the frequency range
(Formby et al.
2007; Meeus et al. 2010; Sheldrake et al. 2015). However, they did not report the ULL
variations across frequency for individual patients.
Dr. Aazh’s tinnitus team and their
international collaborators conducted a pioneering study analysing the data for
over 900 patients in order to explore the pattern of ULLs among patients with
tinnitus and hyperacusis. They assessed the “slope of the ULL thresholds” by
calculating the mean differences in ULLs between 8 and 0.25 kHz (i.e., ULL at 8
kHz minus ULL at 0.25 kHz). Their study
showed that there was a significant correlation between the slope of the ULLs (difference
between ULL at 8 kHz and 0.25 kHz) and ULLmin (Average ULL across 0.25, 0.5, 1,
2, 4 and 8 kHz for the ear with the lower average ULL) (r=0.3,
p<0.001). There was a significant
negative correlation between the slope of the ULLs (8 - 0.25 kHz) and the
scores on Hyperacusis Questionnaire (HQ) (r=-0.13,
p=0.001) (Figure 2). In the other
words, patients with steeper ULLs (larger differences in ULLs thresholds
between 0.25 and 8 kHz) had lower average ULLs in their worse ears and greater
The ULL slope (difference between ULL
at 8 kHz and 0.25 kHz) was ≥20 dB in
115 out of 1004 patients (11.45%).
mean score on the HQ was 22 (SD = 8.9) for patients with the absolute slope of
the ULLs across ears ≥20 dB (n = 115).
This HQ score was significantly higher (worse) than the HQ score of 17 (SD = 9.7)
for patients with absolute ULL slope across ears <20 dB (n = 888) (p<0.001). Thus, large across-frequency changes in ULL are
associated with poorer HQ scores.
The average of ULLmin (Average ULL
across 0.25, 0.5, 1, 2, 4 and 8 kHz for the ear with the lower average ULL) was 66 dB HL(SD = 15.4) for patients with the absolute
slope of the ULLs (difference between ULL at 8 kHz and 0.25 kHz) across ears
≥20 dB (n = 115). This was
significantly lower (worse) than the ULLmin of 80.6 dB HL (SD = 13.1) for
patients with absolute ULL slope across ears <20 dB (n = 888) (p<0.001).
Thus, large across-frequency changes in ULL are associated with more severe
hyperacusis based on ULLmin.
22% of the patients with the slope of the ULLs (difference between ULL at 8 kHz
and 0.25 kHz) across ears ≥20 dB were diagnosed with severe hyperacusis as
indicated by ULL of 30 dB HL or less is measured for at least one of frequency from
0.25, 0.5, 1, 2, 3, 4, 6, and 8 kHz, for at least one ear (Aazh & Moore 2018). This is significantly higher
than the 2% who were diagnosed with severe hyperacusis among patients with ULL slope across ears <20 dB (p<0.001).
This study, for the first time, highlights
that server hyperacusis and greater hyperacusis handicap is characterized by
strong across-frequency variations in ULL.
The strong across-frequency variations in ULLs
for our patients is an indication of adverse reactions only to specific sounds,
which is consistent with the definitions of annoyance and fear hyperacusis (Tyler et al.
2014) and misophonia (Cavanna &
Seri 2015; Kumar et al. 2017; Jastreboff & Jastreboff 2014).
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