Research protocol: Cisplatin-associated ototoxicity amongst patients receiving cancer chemotherapy and the feasibility of an audiological monitoring program.

BACKGROUND: Cisplatin is an anti-cancer chemotherapy drug classified as an alkylating agent. It is used for the treatment of a variety of cancers such as cervical, breast, stomach, prostate, bladder and oesophageal, to name a few. However due to its expansive toxicity profile, patients receiving cisplatin can experience high frequency hearing loss, a side effect known as ototoxicity. The dearth of information on the extent and severity of cisplatin-associated ototoxicity in South Africa prevents the implementation of a context-specific audiological monitoring programme. METHODS: This study aims to determine the extent and severity of ototoxicity amongst patients with cervical cancer, receiving cisplatin-based chemotherapy and hence the feasibility of an ototoxicity monitoring program in the province of KwaZulu-Natal, South Africa. A concurrent mixed methods design will be employed in the study. This longitudinal study will involve interviewing oncology nurses, oncologists, pharmacists and audiologists to assess the level of awareness to ototoxicity, as well as conducting diagnostic audiological evaluations at regular intervals on 78 patients with cervical cancer to ascertain the progression of hearing loss during and after chemotherapy. The feasibility of the monitoring program will be assessed as a parallel process to the audiological evaluations, where patient outcomes and cost implications to the patient and the health sector will be considered. Data will be subjected to statistical analyses so as to strengthen knowledge in the field and inform appropriate policies, and healthcare providers. DISCUSSION: This study is the first longitudinal study in South Africa to determine the ototoxic effects of cisplatin therapy on patients diagnosed with cervical cancer. Thus, the results generated from this study is likely to bring novel information to the fore using an evidence-based approach that will influence policy and clinical practice which can vastly improve the quality of life of patients undergoing chemotherapy. Mitigation of any further loss in the quality of life of affected patients is of paramount importance and the data generated from this project can lay the basis for further effective dialogue towards policy formulation on an ototoxic monitoring programme and the resultant strengthening of health systems in limited resource settings.

Cochlear function in patients with chronic kidney disease.

OBJECTIVE: To evaluate cochlear functioning in patients (18-45 years old) with varying stages of chronic kidney disease (CKD). Using purposive sampling, 50 participants, 10 in each of the 5 stages of CKD, were selected and underwent pure tone audiometric testing and distortion product otoacoustic emissions (DPOAEs). RESULTS: Significant differences (p < 0.05) were found between pure tone audiometry and DPOAEs in detecting early cochlear dysfunction in the high-frequency range in stages 3 (6,000/5,000 Hz; p = 0.00), 4 (6,000/5,000 Hz; p < 0.03) and 5 (4,000/3,333 Hz; p < 0.01, 8,000/6,667 Hz: p < 0.05) with DPOAEs being more sensitive in identifying early cochlear dysfunction. Patients in stages 1 and 2 presented with normal puretone thresholds and DPOAEs, suggesting that cochlear functioning in these patients was normal. Early cochlear dysfunction, thereby indicating a subclinical hearing loss, was identified in stages 3, 4 and 5 by DPOAE testing. In addition, blood test results, drug intake and concomitant conditions were recorded and analysed which suggested a relationship between reduced cochlear functioning and increased electrolyte levels, treatment regimens and concomitant conditions. CONCLUSION: Participants in the later stages of CKD presented with early cochlear dysfunction, presenting with subclinical hearing loss. It was postulated that this subclinical hearing loss resulted from a combination of electrolytic, urea and creatinine imbalances, together with concomitant medical conditions and ototoxic drug intake. It was concluded that audiological monitoring be included in the management of patients with CKD and that DPOAEs be introduced as part of the test battery to monitor cochlear function in patients with varying degrees of CKD.

Diagnostic reference data for the monaural brain-stem auditory evoked response (BAER).

The objective of the investigation was to establish diagnostic reference data for the normal BAER. BAERs were elicited from the target (R) ear using clicks presented at 70dBnHL. Relevant latency and amplitude data were obtained from 60 selected normal hearing Indian undergraduate females (N = 30; mean age = 20.33 years) and male (N = 30; mean age = 21.33 years) students aged between 18 and 25 years (mean age = 20.73 years). Diagnostic reference data were established for the absolute latencies of peaks I to VI; relative latencies of peaks I-III; III-V and I-V; absolute amplitudes of peaks I and V and the relative amplitude ratio of peaks V:I. These results are discussed in terms of the literature and implications for clinical application and further research.