4
Treating Tinnitus in Patients with Otologic Conditions
In this chapter we share our perspective on treating patients with tinnitus in whom otologic pathology has been diagnosed, and the tinnitus therapy must be interleaved with the treatment of the causative condition. This is of particular importance where the treatment may exacerbate tinnitus. As will be discussed in detail here, treatment of Meniere’s disease with gentamicin ablation therapy carries a risk of both increased hearing loss and more intense tinnitus, as does the trans-labyrinthine removal of a vestibular schwannoma. Tinnitus treatment that is integrated within the overall treatment has an increased likelihood of success.
Also implicit within this model is the idea of a multidisciplinary team. The utility of surgical teamwork and collaboration is well established within neuro-otology, but in the case of tinnitus therapy, the medical team must expand to include the tinnitus therapist, of whatever discipline. The perspectives brought by each individual from his or her own discipline will be invaluable, and it is in such multidisciplinary collaborative models that hope lies for new and effective treatments of tinnitus.
Tinnitus treatment protocols in three specific otologic conditions are described: Meniere’s disease, vestibular schwannoma, and unilateral sudden sensorineural hearing loss.
Although the treatment approaches to patients with these conditions are described in specific detail, there are insights that will assist the reader in treating patients with other otologic conditions with which tinnitus is associated.
Treating Tinnitus in Patients with Meniere’s Disease
Tinnitus is a defining feature of Meniere’s disease, the others being episodic rotary vertigo and hearing loss (AAO-HNS, 1995). There are some indications that patients with Meniere’s disease have specific tinnitus experiences. Stouffer and Tyler (1990) noted that patients with Meniere’s disease had significantly higher ratings of tinnitus severity and annoyance than patients with other etiologies. Douek and Reid (1968) found that patients with tinnitus as a symptom of Meniere’s disease consistently matched their tinnitus to a low-frequency tone (usually in the range 125–250 Hz), unlike the majority of tinnitus patients, who match tinnitus to a pitch above 3000 Hz (Tyler, 2000). Erlandsson et al (1996) noted that those patients with anxiety and depression associated with Meniere’s disease found their tinnitus intolerable. The finding that patients with Meniere’s disease consider the impact of their symptoms more severe if they are anxious or depressed will not surprise those clinicians who see such patients, and a screen for treatable anxiety or depression, such as the Hospital Anxiety and Depression Scale (HADS; Zigmond and Snaith, 1983), should be considered.
A therapeutic strategy for tinnitus in Meniere’s disease should account for these specific issues. The combination of tinnitus and hearing loss should cause one to consider amplification, with a prescription that is mindful of both potential hearing fluctuation and loudness recruitment. Although the hearing loss will be unilateral in the majority of cases, and thus may not fall within some traditional amplification protocols, there is qualitative and quantitative evidence that mild unilateral hearing loss may be associated with hearing handicap (Harford and Barry, 1965; Newman et al, 1997).
Medical and surgical treatments for Meniere’s disease have the aim of vertigo control, and may have a risk of exacerbating tinnitus and hearing loss. Vestibular nerve section has been demonstrated to remove input from a labyrinth with Meniere’s disease. The ablation of the medial efferent auditory input to a cochlea when the inferior vestibular nerve is sectioned, containing medial efferent fibers (Rasmussen, 1946), which then join the cochlear nerve at the anastomosis of Oort (1918), has a hypothetical risk to frequency selectivity and to the coding of tinnitus intensity by the efferent system. Scharf et al (1997) found, however, that the performance of 16 patients on psychoacoustic testing was not degraded following vestibular nerve section. Baguley et al (2002) have reviewed the effect of vestibular nerve section on tinnitus and found that in the majority of patients, tinnitus remains at preoperative levels or improves. The use of intratympanic gentamicin to perform a chemical labyrinthectomy for vertigo control has become widespread. Reports of the effect of this procedure on tinnitus are variable. Several authors have reported that tinnitus may improve or even abate after such treatment (Atlas and Parnes, 1999; Silverstein et al, 1999), but because the procedure involves a potential risk to cochlear function (Berryhill and Graham, 2002), one should be mindful of the possibility of tinnitus exacerbation.
A note of caution is offered by Vernon et al (1980), who reported that following the successful control of vertigo, some patients with Meniere’s disease focus more on their tinnitus and hence are more distressed by it. This is supporting evidence for the approach described herein, where tinnitus therapy is coincident with interventions for the vestibular and hearing symptoms of Meniere’s disease.
Treatment Protocol
There are several elements of tinnitus treatment specific to patients with Meniere’s disease, addressing the issues just described, and these are summarized in Table 4–1.
| Specific Therapy | When Undertaken? |
|---|---|
| Counseling regarding association between tinnitus and disabling rotary vertigo | Ongoing |
| Fitting multiprogram hearing aid | Second session if appropriate |
| Relaxation therapy, possibly utilizing biofeedback | Introduce in second or third session as appropriate |
| Onward referral for depression and anxiety | If indicated by HADS score |
| Hearing rehabilitation (speech reading, hearing tactics, auditory training) | Ongoing if hearing loss a significant factor |
| HADS, Hospital Anxiety and Depression Scale. | |
ASSOCIATION WITH VERTIGO
In many patients, increased tinnitus may be an element of the prodrome to an attack of vertigo. As such, the strong association of tinnitus with disabling rotary vertigo can be a factor in the persistence of distress and needs to be addressed in counseling. Medical or surgical treatment may reduce the incidence and severity of such attacks, but the psychological association with tinnitus may well persist beyond the physical link. As already mentioned, an observation has been made that when vertigo resolves, tinnitus may apparently worsen (Vernon et al, 1980). As such, a patient with Meniere’s disease who is vertigo free may be in urgent need of intervention for tinnitus.
SOUND THERAPY AND FLUCTUATING HEARING LOSS
The hearing loss associated with Meniere’s disease is typically unilateral and low frequency, and as such is not commonly associated with significant hearing handicap. It does, however, have significant consequences for the use of sound therapy for tinnitus. If a noise generator is to be used, one should be mindful of the fact that the lower frequency element of the noise will be attenuated in the perception of the patient, and that this may well be the frequency region where the tinnitus is matched. As such, the fitting of a device that produces sufficient energy in the low frequencies to be effective in reducing the starkness of the tinnitus is indicated. A multiprogram device, with one program producing more low-frequency noise, also may be helpful.
More commonly undertaken in our clinic is the unilateral fitting of a multiple memory hearing aid for patients with unilateral Meniere’s disease. Amplification is almost always essential in bilateral Meniere’s disease. The hearing aids fitted should be carefully programmed to the most usual audiometric configuration, and one should be mindful of the need to use appropriate compression in these patients who are likely to experience recruitment. Where there is evidence of threshold fluctuation, programs within the aid should be utilized to meet amplification needs at times of exacerbation or improvement in hearing, and the patient should be carefully instructed in their use. Additionally, instruction in speech reading, hearing tactics, and auditory training may be indicated.
STRESS, TINNITUS, AND MENIERE’S DISEASE
The relationships between stress, tinnitus, and Meniere’s disease are complex and require some skill on the behalf of the clinician for any given individual. Careful history taking in this regard is essential. Although progressive muscle relaxation therapy has a role, a proportion of patients may need to use biofeedback to facilitate learning to reduce chronic sympathetic autonomic arousal. Additionally, sleep hygiene tactics may be introduced as an element of relaxation therapy (McKenna, 2000).
ONWARD REFERRAL FOR DEPRESSION AND ANXIETY
Given the well-established incidence of stress and anxiety in the Meniere’s disease population, there is the possibility that these symptoms may be evident in the history taken in the tinnitus clinic, and may also have an association with tinnitus. Careful use of a screening tool such as the HADS (Bjelland et al, 2002; Zigmond and Snaith, 1983) may be useful with tinnitus patients (Andersson et al, 2003; Svedlund et al, 2002).
Treating Tinnitus in Patients with a Vestibular Schwannoma
Tinnitus is a common symptom reported in patients diagnosed with vestibular schwannoma, having been stated as being present in 73% of cases (N = 473, Moffat et al, 1998) and being the principal presenting symptom in 11%. Hypotheses regarding the generation of tinnitus by this benign tumor arising from the vestibular nerve include ephaptic coupling (cross-talk of fibers within a compressed cochlear nerve) (Moller, 1984), a cochlear lesion due to ischemia by the tumor compromising blood flow in the labyrinthine artery, which runs through the internal auditory canal, or by biochemical degradation of the cochlea (Schuknecht, 1993), and the potential dysfunction of the medial auditory efferent pathway within the inferior vestibular nerve due to compression in the internal auditory canal (Baguley et al, 2001).
Intriguingly, in many cases the tinnitus persists after surgical removal of the tumor (see Baguley et al, 2001, for a review), being persistently present in 60% of patients undergoing translabyrinthine removal. Reports indicate that this postoperative tinnitus is severe in a proportion of cases ranging from 2.5% (Baguley et al, 1992) to 6% (Andersson et al, 1997). As with preoperative tinnitus, the mechanism of postoperative tinnitus remains unclear: of the hypotheses mentioned earlier, that of ephaptic coupling could be applied to the postoperative situation because cross-talk has been demonstrated in damaged peripheral nerves (Seltzer and Devor, 1979). Tumor removal necessitates section of the inferior and superior vestibular nerves, and so efferent dysfunction will be total due to the ablation of efferent fibers within the inferior vestibular nerve. However, an argument against this representing a significant factor in tinnitus persistence is found in studies that indicate that patients undergoing successful hearing preservation surgery to remove a vestibular schwannoma are less likely to have postoperative tinnitus than those undergoing translabyrinthine surgery (Catalano and Post, 1996). When such hearing preservation surgery is successful cochlear nerve function is by definition preserved, although the hearing may be slightly affected, but the vestibular nerve is sectioned (and thus efferent input ablated) as the tumor is removed.
Although the studies already cited have demonstrated that severely distressing tinnitus is not common following vestibular schwannoma removal, there are indications (Baguley et al, 1999) that the identification of patients with severe and distressing tinnitus preoperatively may allow therapy to commence while the patient awaits surgery (or is enrolled in a watch, wait, and rescan program), in the knowledge that in many patients tinnitus persists. It may be, however, that after diagnosis and discussion as to the intended surgical or other treatment of the tumor, the patient is able to cope better knowing the cause of the tinnitus; the flip side is that the tinnitus could be exacerbated.
The use of a questionnaire such as the Tinnitus Handicap Inventory (Newman et al, 1996,1998) at diagnosis would allow the therapist to identify those patients in whom the tinnitus symptom is associated with significant distress and thus justifies therapy (Baguley and Andersson, 2003). In those patients in whom preoperative tinnitus abates (15–18% of patients undergoing translabyrinthine removal; Andersson et al, 1997; Baguley at al, 1992), this therapy will have made the wait for surgery more bearable. In those in whom the tinnitus persists, such therapy will facilitate habituation to tinnitus in the postoperative period. One should also be mindful of those patients who do not experience tinnitus preoperatively but do following surgery (27–35%; Andersson et al, 1997; Baguley et al, 1992). These patients should undergo careful counseling about this possibility and the need not to be alarmed if tinnitus does emerge postsurgery.
Treatment Protocols
In our facility, patients with vestibular schwannoma and troublesome tinnitus are seen in the tinnitus clinic after they have been seen in the neurootology clinic and tinnitus has been identified as a problem. Treatment elements specific to patients with a vestibular schwannoma and tinnitus are summarized in Table 4–2.
| Specific Therapy | When Undertaken? |
|---|---|
| Counseling regarding the association between the tinnitus and vestibular schwannoma and any treatment | Pre- and postoperative |
| Begin therapy at diagnosis for patients in watch, wait, scan, and rescan program | Appointment within 1 month of diagnosis Hearing aids and tinnitus and vestibular rehabilitation as indicated |
| Fitting CROS, BICROS, transcranial CROS, and contralateral BAHA | Postoperative |
| Relaxation therapy (progressive muscle relaxation or biofeedback) | Second or third session |
| Hearing therapy | Ongoing as patient needs |
| Onward referral for anxiety and depression | If indicated by HADS score |
| BAHA, Bone Anchored Hearing Aid; BICROS, Bilateral Contralateral Routing of Sound; CROS, contralateral routing of signal; HADS, Hospital Anxiety and Depression Scale. | |
INFORMATION ABOUT MECHANISMS
Even if information about tinnitus is given to patients diagnosed with a vestibular schwannoma, few seem to be able to assimilate it; this is not surprising, given the impact of tumor diagnosis and a possible neurosurgical procedure. There is an opportunity to inform patients troubled by tinnitus associated with a vestibular schwannoma, either pre- or postoperatively, or a watch, wait, and rescan program of the mechanisms that may be implicated in their tinnitus experience. Preoperatively, and in the watch, wait, and rescan group, this can include discussion of cochlear involvement (either by ischemia or biochemical degradation) and, postoperatively, using phantom limb analogies. These mechanisms are briefly reviewed above and in detail elsewhere (Baguley et al, 2001). Patients with gaze-modulated tinnitus may find explanation of this phenomenon particularly beneficial, although one must acknowledge that there are many unanswered questions.
WATCH, WAIT, AND RESCAN
With the increased popularity of this strategy (Hoistad et al, 2001; Sandooram et al, 2003), specific consideration should be given to tinnitus and the need for therapy. There is a tendency for such patients not to be considered for tinnitus treatment (nor indeed for auditory or vestibular rehabilitation), though this may be very beneficial. Of specific note is that some patients in this group become very concerned about changes in tinnitus, fearing that this may signal a sudden growth in tumor volume. Moving up magnetic resonance imaging scan appointments is indicated in such situations.
SOUND ENRICHMENT IS CONTRAINDICATED
Patients who undergo a translabyrinthine removal of a vestibular schwannoma, or indeed a failed hearing preservation approach, have a permanent unilateral profound sensorineural hearing loss. As such, the often used strategy of sound enrichment from a source of low-level, continuous background noise is contraindicated because such patients will find it markedly harder to discriminate any other sound against that background. This exacerbation of hearing handicap should be avoided.
POSTOPERATIVE HYPERACUSIS
It has been noted anecdotally that patients who undergo vestibular schwannoma removal in which hearing is sacrificed in the tumor ear may experience hyperacusis in the contralateral ear in the immediate postoperative period, which then resolves. This has not been empirically verified, and indeed this would be problematic to accomplish, but an explanation may be helpful for some patients. A reasonable discussion would involve the effect on the auditory system of sudden deafferentation, and of the efferent pathways that may then be adversely affected.
CROS, BICROS (Bilateral Contralateral Routing of Sound), TRANSCRANIAL CROS, AND CONTRALATERAL BAHA (Bone Anchored Hearing Aid)
Contralateral routing of signal (CROS) hearing aid devices offer the possibility of some awareness of sound presented to a deaf ear. Detailed protocols for the fitting of such devices are readily available (see Dillon, 2001; Valente et al, 2002, for examples). Little evidence is available regarding the efficacy of such devices in the vestibular schwannoma patient group, though evidence is emerging that benefit may be achieved with the use of a contralateral bone-anchored hearing aid in speech discrimination in some tasks (Bosman et al, 2003; Niparko et al, 2003; Wazen et al, 2003). Even less evidence is available regarding the effect of such devices on tinnitus. Given the phantom limb analogy with tinnitus following vestibular schwannoma removal, it is possible that providing sound input that appears to derive from a deaf ear may reduce tinnitus, a potential analogy being that a visual input appearing to derive from a phantom hand reduces phantom pain (Ramachandran and Rogers-Ramachandran, 1996). Further work is needed in this area, but a trial of CROS devices in such patients may be cautiously attempted.
Treating Tinnitus in Patients with Unilateral Sudden Sensorineural Hearing Loss
A sudden sensorineural hearing loss is considered to be an otologic emergency (Arts, 1998; Hughes, 1998) and necessitates urgent treatment. Little attention has been paid, however, to the consequence to the patient of a sudden sensorineural hearing loss in terms of tinnitus handicap.
The perceived hearing handicap of patients with unilateral hearing loss has been considered (Newman et al, 1997). A series of 43 patients with unilaterally normal hearing completed the Hearing Handicap Inventory for Adults (Newman et al, 1990). It was noted that almost three quarters (73%) reported mild or greater hearing handicap, which was indicative of “communication and psychosocial problems,” despite the normal contralateral ear. The patients were recruited from otolaryngology outpatients, but it was not recorded how long the patients had experienced the unilateral hearing loss, or if the loss had been gradual or sudden. It might be expected that the sudden and possibly traumatic onset of a unilateral hearing loss involves more handicap than a loss of insidious onset.
A more recent study (Chiossoine-Kerdel et al, 2000) investigated the tinnitus handicap associated with sudden sensorineural hearing loss in a group of patients utilizing the Hearing Handicap Inventory for Adults and the Tinnitus Handicap Inventory as outcome measures. Tinnitus was reported by 14 of the 21 patients who responded to the mailed questionnaires from a total of 38 patients identified as having undergone a sudden sensorineural hearing loss in the years 1988 to 1997. The median total Tinnitus Handicap Inventory score for those with tinnitus was 20 (interquartile range 52), and in 4 patients of the 14 with tinnitus (28.6%), the tinnitus handicap was moderate or severe. The onset of tinnitus was coincident with sudden sensorineural hearing loss in 8 patients (57% of the 14 with tinnitus) and occurred within 48 hours in the remaining 6 (43%). In 18 patients (86% of the 21 patients) a significant hearing handicap was demonstrated.
Thus it may be inferred that distressing tinnitus is not unusual following a sudden sensorineural hearing loss, and that therapy for both issues in hearing and tinnitus should be undertaken with such patients on a systematic basis in conjunction with medical treatment of the condition at the time of admission for a sudden hearing loss.
| Specific Therapy | When Undertaken? |
|---|---|
| Early audiologic intervention | On otolaryngology ward |
| Information regarding mechanisms | Initial postdischarge session |
| Hearing rehabilitation | Ongoing in first 3 months |
Treatment Protocols (Table 4–3)
EARLY INTERVENTION
With the consensus that sudden sensorineural hearing loss needs urgent medical treatment, the majority of patients will be admitted to the otolaryngology ward. At this point, the patient may well be anxious and upset. Additionally, the patient may not yet be aware of the potential handicap associated with a unilateral sudden sensorineural hearing loss due to the structured and limited conversations that occur in a hospital ward. However, the admission represents an opportunity for early discussion and support that may prove beneficial on discharge.
INFORMATION REGARDING MECHANISMS
As with the other otologic pathologies already described, clear and modern explanations of tinnitus mechanisms are beneficial. In the case of sudden sensorineural hearing loss, reference could be made to phantom limb analogies.
HEARING THERAPY
For many patients the tinnitus handicap following sudden sensorineural hearing loss is intimately bound up with hearing handicap. As such, instruction in hearing tactics, speech reading, and structured practice in auditory discrimination is of significant potential benefit in this patient group.
Conclusion
This chapter has discussed the specific strategies indicated in tinnitus therapy in three otologic pathologies. In all cases teamwork is key, and it is important to be aware that the treatment of the health condition may affect or even produce tinnitus. Counseling the patient about tinnitus and providing tinnitus treatment when necessary are vital to the overall success of the patient’s care.
Acknowledgments
Tinnitus research in the Cambridge Departments of Otology and Audiology have been supported by the British Tinnitus Association, the Meniere’s Society, and the de Turckheim Fund of Trinity College, Cambridge. We would like to express our thanks.
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