对于突发性耳聋神经康复治疗方法

This article describes a behavioral treatment approach for SSHL. The CIST protocol merely requires the use of easily available devices. A comparison of the treatment effects of CIST + SCT with those of SCT alone revealed significantly better hearing improvements with the CIST + SCT treatment. No apparent side effects were associated with the CIST protocol. The cost of CIST is markedly lower than other newly suggested treatments (including a stellate ganglion block and hyperbaric oxygen therapy). The CIST protocol represents an effective, inexpensive, easy, and safe treatment for SSHL; however, several important points must be considered. One point is the prevention of acoustic trauma. Although the maximal volume settings of recent commercial portable music players are limited to remain below the harmful levels, the sound level needs to be observed when a large adjustment is made to the equalizer settings or when a headphone amplifier is used. The second point is ‘cross hearing’. The purpose of the CIST procedure is to enable SSHL patients to actively use their affected ear for listening. When patients develop severe hearing loss, they may still hear sounds with the intact ear despite plugging. The third point is ‘accidents’. In the case of traditional pharmacotherapy, the intact ear is not plugged, and thus SSHL patients can pick up environmental sounds via this intact ear. On the other hand, plugging and music listening inherent to the CIST protocol seal patients from environmental sounds, and thus the accident hazard is likely increased. Therefore, the CIST protocol should be conducted in a safe environment.

Unlike pharmacotherapy, the CIST protocol has no limitations concerning medications, allergies, or other diseases such as diabetes, hypertension, and hyperlipidemia. However, the limitation of this protocol is that it is intended for patients who are able to listen to sounds with their affected ear. As such, the CIST protocol is not suited for SSHL patients with severe hearing loss. This protocol is applied to acute stage SSHL (days since SSHL onset ≤ 5) because previous studies reported that a shorter time delay between the onset of SSHL and the start of treatment led to better hearing recovery². It remains elusive whether there is a time restriction for starting the CIST protocol. Moreover, the optimum duration of the CIST protocol and the total music listening time require further investigation.

This protocol utilizes the corticosteroid therapy in addition to CIST. At present, corticosteroids are the most commonly used treatment for SSHL, and therefore it is ethically not feasible to stop this treatment. However, recent triple-blinded SSHL treatment studies¹⁴ revealed that the recovery of non-treated patients was similar to that of patients who had received corticosteroids. Even though one cannot exclude the possibility that the combination of CIST + SCT led to the results obtained, it appears reasonable to assume that CIST alone will be beneficial, especially for patients with diseases that are worsened by corticosteroids such as infections, diabetes, and glaucoma.

In this protocol, patients are hospitalized in order to avoid accidents. However, SSHL patients often cannot be hospitalized because of work, family, and financial reasons. The utilization of a hearing aid may allow these outpatients to perform the CIST protocol. SSHL patients who wear a hearing aid in their affected ear are ‘functionally’ exposed to an enriched acoustic environment, are not in danger to be exposed to harmful sound levels, and are able to detect warning sound signals. However, the daily monitoring of hearing threshold levels and appropriate adjustments to the hearing aid settings would be necessary since hearing capability of SSHL patients can improve rapidly. Generally, the CIST protocol will not disturb other treatment approaches and may actually manifest a synergic effect when used in combination with other SSHL treatment strategies.

In the present study, a limited number of SSHL patients underwent the CIST protocol, and the participants were not randomized to the different treatment conditions. Thus, a randomized controlled study including a larger number of patients should be executed in the future. Moreover, the effectiveness of the CIST protocol should be investigated in patients with different types of hearing loss. Further, in the present study, all participants who performed the CIST protocol also received the corticosteroid therapy. Therefore, it remains unresolved whether the CIST protocol alone can improve the hearing ability of SSHL patients. It would be valuable to perform a randomized controlled study in which SSHL patients, for whom corticosteroids may cause severe side effects (such asinfectious diseases or diabetes mellitus), would either merely receive the CIST protocol or merely a standard corticosteroid therapy. Notably, in our previous report²³, the effects of the CIST protocol within the human auditory cortex were examined by means of magnetoencephalography³⁵. The results showed that the CIST protocol could have prevented maladaptive cortical reorganization in the human primary and non-primary auditory cortices. Of course, it is difficult to conduct neuroimaging studies in practices and hospitals; however, speech test, hearing in noise test³⁶, and tinnitus related examinations³⁷ may contribute to reveal the functional plasticity in the central auditory system induced by the CIST protocol. Eventually, even though the CIST protocol is in a very early stage in development, and although further investigations are needed, the CIST protocol as an effective, inexpensive, and safe treatment option can complement the corticosteroid therapy, which may induce severe and potentially lethal side effects.