Audiological Interests in Ototoxicity Monitoring
Audiologic monitoring for ototoxicity is primarily performed for two purposes:
- early detection of changes to hearing status presumably attributed to a drug/treatment regime so that changes in the drug regimen may be considered, and
- audiologic intervention when handicapping hearing impairment has occurred. These clinical goals are differentiated in the following.
The term ototoxicity monitoring is generally taken to express the principle of early identification, yet the concept also embraces the principle of early intervention. For example, when changes are detected early, the physician can be alerted so that alternative treatment protocols, possibly with less ototoxic medications, may be considered. Furthermore, when clinically significant changes occur, especially hearing deterioration that has migrated into the speech frequencies, the purpose of a monitoring program becomes to assist the patient and/or patient’s family to maintain effective communication, especially as hearing loss progresses. Unfortunately, this degree of hearing impairment may be unavoidable even with proactive ototoxicity monitoring, as the priority is effective treatment of the disease via the given drug therapy.
These two major objectives of an ototoxicity monitoring program often may create substantially different roles for the audiologist than conventional practice. Landier (1998) makes it clear that it would be advantageous for audiologists to be well aware of the same sort of considerations of the environment in which the patient is being sought and/or examined, as the logistical issues are not trivial. For example, oncology nurses are essential contact persons for the successful implementation of ototoxicity-monitoring protocols in cancer chemotherapy patients, just as recognizing key nursing personal in well-baby and newborn intensive care nurseries is essential for successful implementation of newborn hearing-screening programs. At the same time, the audiologist’s native skills and talents are/should be paramount in the establishment and management of the program, including in-service education, and certainly the interpretation of results.
Once ototoxicity-monitoring protocols are established, the audiologist can accomplish the second objective of such scrutiny, that is, the management of a hearing loss that is not treatable medically. Such assistance to the patient/patient’s family may include counseling, communication strategies, and prescribing amplification and/or assistive listening device(s).
Only the audiologist is endowed by their professional training with the ability to achieve both objectives of ototoxicity monitoring. The audiologist thus should take the lead in developing ototoxicity-monitoring programs, driven by the dual goals, again, of preventing or minimizing hearing loss and helping the patient to maintain the most effective hearing communication possible. These clearly are important ‘quality of life’ issues and quality of life is now recognized as a global imperative, whatever the medical management. Consequently, that the patient may suffer a serious and possibly life-threatening illness does not diminish the importance of these issues.
Audiologic monitoring for ototoxicity has been a very active area of research. It is outside the scope of this document to review such research, beyond that of direct topical interest. Still, it is worth concluding this section with a brief note. Namely, on-going work at a number of clinical and research centers are generating results that provide or are expected to permit comparisons among monitoring and analysis techniques for a variety of patient populations. Furthermore, new drugs are being developed that appear to have excellent therapeutic efficacy without ototoxic side effects (Campbell et al. 2003a). Still, other drugs and dietary supplements are being evaluated specifically to prevent ototoxicity when delivered either before or in combination with ototoxic drugs (see Campbell, 2007 [cf. 287-286]; Campbell et al., 2003b, 2007; Kopke et al. 1997; Sha & Schacht 2000; Doolittle et al. 2001; Blakley et al. 2002). The results of research on otoprotectants might lead to the assumption that the need for ototoxicity monitoring will disappear with effective ototoxicity prevention. It seems more likely, however, that monitoring will be essential to ensure effectiveness of such counter measures.
Source: American Academy of Audiology
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