Table 1: Patients with tinnitus as main complaint were compared with patients with cervical pain as main complaint.

Figure 1: The maximal intensity of the sensation and the prevalence of the feeling that the sensation is hard to withstand for tinnitus and for cervical pain.

Patients with cervical pain as leading complaint: Multivariate analysis in patients with cervical pain as principal complaint showed that the VAS of the mean cervical pain and gender were statistically significant for fatigue. In women, a VAS of mean cervical pain exceeding 39 millimetre raises the prevalence of fatigue from 57% to 90% and with a VAS of mean cervical pain of more than 47 millimetre the prevalence of hard to withstand cervical pain increases from 53% to 77% (Figure 2). In men, the VAS of mean cervical pain was 70 and 64 millimetres respectively for the same increases in prevalence.

Figure 2: The mean intensity of cervical pain and the prevalence of fatigue and the feeling that cervical pain is hard to withstand for women and men.

Patients with tinnitus as leading complaint: In patients with tinnitus as major complaint, multivariate analysis indicated that the VAS of maximal tinnitus and the presence of cervical pain were statistically significant associated with fatigue. In patients with cervical pain and tinnitus, a VAS of maximal tinnitus exceeding 59 millimetre raises the prevalence of fatigue from 40% to 88% and with a VAS of maximal tinnitus of more than 71 millimetre the prevalence of hard to withstand tinnitus increases from 32% to 65% (Figure 3). In patients with tinnitus and no cervical pain, the prevalence of fatigue and of hard to withstand tinnitus remained 40% and 32%, respectively.

Figure 3: The maximal intensity of tinnitus and the prevalence of fatigue and the feeling that tinnitus is hard to withstand in patients with and without cervical pain.

Discussion

This study indicates that it is harder to withstand cervical pain than tinnitus with a higher prevalence of fatigue and impaired work performance in cervical pain patients. The feeling that the sensation is hard to withstand is closely related to fatigue. Our analyses highlight the importance of fatigue as a potential mediator of the deleterious effects of pain and tinnitus on individual functioning. Female gender and the presence of cervical pain makes patients more accessible for fatigue. Tolerance against tinnitus depends on the perceived maximal intensity of tinnitus, but also of the presence of cervical pain. Cervical pain may reinforce the irritating awareness of tinnitus. Tinnitus and pain are sensory-perceptual conditions linked with negative affections9. Percepts reach only awareness when increased neuronal activity in the primary sensory or auditory cortex is connected to brain networks [1]. The distress network of tinnitus and pain overlaps each other. A pain or an auditory stimulus delivered near threshold becomes only consciously perceived when the dorsal anterior cingulate cortex and anterior insula are activated. The intensity of perceived pain and auditory stimuli relates to the degree of activity in the dorsal anterior cingulate cortex and anterior insula [2]. The frontostratial circuits has a pivotal role in the forming and continuation of tinnitus and chronic pain [9]. Especially, the ventromedial prefrontal cortex and the nucleus accumbens estimate the relevance of sensory stimuli and manage the information flow via descending pathways [3-9]. However, there are also meaningful differences between tinnitus and chronic pain [9]. Pain induces a negative affection for the protection of vital functions. Auditory signals may only become inconvenient when the awareness persists for a long time. Our analysis indicates that the perceived intensity of pain provoked annoyance earlier compared to the perceived intensity of tinnitus. Male patients could withstand the intensity of cervical pain better than female, especially in the range of VAS of mean cervical pain from 47 to 64 millimetre. Women are at higher risk of both developing and reporting pain [11]. Increased functional connectivity of the prefrontal cortex to the nucleus accumbens is predictive of pain persistence and there are sex-dependent differences in processes that regulate the intrinsic excitability of these neurons [9-12]. Sex differences involve the organization of the insula and anterior cingulate cortex together with the emotional-arousal reactivity in patients with chronic pain [13]. We did not find an influence of gender on withstanding tinnitus. Tinnitus can be switch off by feedback from the limbic system, which can obstruct the tinnitus signal before reaching the auditory cortex [9]. If the limbic regions are affected, this “noise-cancellation” mechanism can pull down and chronic tinnitus results. Such a limbic gating system also exists for the somatosensory system [9]. It is not only responsible for the unpleasantness of pain but also for modulating its intensity. The ventromedial prefrontal cortex and the nucleus accumbens are implicated in the persistence of pain [12]. Both pain and tinnitus can have an additive effect on the frontostriatal circuits. In our study, the presence of cervical pain made it harder to withstand tinnitus in the range of VAS of mean intensity of tinnitus exceeding 71 millimetres. Tolerance against tinnitus depends on the perceived maximal intensity of tinnitus, but also of the presence of cervical pain. Our analyses highlight the importance of fatigue as potential mediator of the deleterious effects of pain and tinnitus on individual functioning. A strong positive correlation between fatigue and the perceived intensity of pain and tinnitus was observed. Fatigue is not only associated with the experience of pain and tinnitus, but it may also predict how well people maintain activity in the face of pain or tinnitus [14,15]. Sleep disturbances, resulting in fatigue, strongly predicts lower tinnitus tolerance [16]. Tinnitus may interfere with sleep by the amplification of internally perceived noise during times of low environmental noise or due to an increased focus on tinnitus and undue anxiety [16]. Sleep impairment is also a predictor of long-standing pain, possibly as a result of changes in endogenous pain inhibition associated with an attenuated activation of the nucleus accumbens [17]. This study has limitations. The first limitation is its retrospective kind and a prospective follow-up study is advocated to confirm these results and the conclusions. Another limitation is that the lack of measurement of the perceived intensity of cervical pain in patients with tinnitus as major complaint. A VAS-measurement of cervical pain together with a VAS-measurement of cervical pain in this group of patients could better differentiate which influence on withstanding tinnitus is the most. Hereafter, prospective studies are required with an estimate of the intensity of cervical pain in patients with tinnitus.

Conclusion

Tinnitus and chronic pain are related to structural and functional brain changes that show a striking overlap between both conditions. A limbic gating system exists for both the somatosensory system and the auditory system, which is responsible not only for creating the unpleasantness of pain and tinnitus but also for modulating its intensity. The tolerance, the ability to withstand the “unpleasantness” of the percept, for tinnitus and pain depends on the perceived intensity of the sensation. However, the perceived intensity of pain provoked annoyance earlier compared to the perceived intensity of tinnitus. Cervical pain may reinforce and maintain the negative awareness of tinnitus. For a better withstanding of tinnitus, we advise to reduce the perceived maximal intensity of tinnitus and to treat cervical pain and fatigue.

Conflict of Interest

The authors declare no potential conflict of interest

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Henk M Koning, Department of Pain therapy, Pain Clinic De Bilt, De Bilt, The Netherlands, E-mail: hmkoning@pijnkliniekdebilt.nl Phone: +31302040753

Paper submitted on January 25, 2021; and Accepted on February 10, 2021

Citation: Henk M Koning,Bas C ter Meulen. Is Pain Harder To Withstand Than Tinnitus?. International Tinnitus Journal. 2021;25(1):46-50.