Developing a Hearing Screening Material for the Ghanaian Adult Population

Abstract

Background: Hearing loss affects a significant number of people worldwide, with an estimated 1.5 billion people experiencing varying degrees of hearing impairment. Unfortunately, many hearing loss cases, especially in low- and -middle-income countries such as Ghana, go undetected and untreated. Early identification through a hearing screening protocol is a key first step to curbing the burden of hearing loss. While pure-tone audiometry remains a relevant hearing screening method, it is important to evaluate a person’s speech perception, and self-perceived hearing difficulties during a screening program, as these reflect their practical hearing capabilities in everyday communication situations. Advancements in hearing screening tools, such as the automated Digit Triplet Test and self-reported hearing handicap questionnaires, offer a solution for early identification of hearing loss. Objective: The general objective of this research was to develop hearing screening material for the adult Ghanaian population. Methods and Results: The first part of this doctoral thesis provided a descriptive and analytic overview of the historical development of Audiology services in Ghana, including an examination of the available and geographical distribution of hearing-related services in the country. Results revealed the significant progress that has been made in improving access to hearing healthcare in Ghana, as well as some challenges such as financial constraints, uneven distribution of audiological facilities, under-resourced facilities, lack of a national policy on hearing health, and lack of coverage of audiological services under the National Health Insurance Scheme. The second part of the thesis describes the different stages for the development of the translated and cross-culturally adapted version of the Revised Hearing Handicap Inventory Screening tool (RHHI-S; Cassarly et al., 2020), into Asante-Twi. The evaluation of the Asante-Twi version of the RHHI-S was conducted with a sample comprising 50 individuals with normal hearing and revealed that this adapted version of the questionnaire shows high internal consistency, with a Cronbach's alpha coefficient of α = 0.936. However, further psychometric properties (predictive validity, construct validity, concurrent validity, internal consistency, reliability, and test-retest reliability) of the Asante-Twi version of the RHHI-S must be assessed before its use for hearing screening. The third part of the thesis describes the different stages for the adaptation of the Digit Triplet Test (DTT; ref), into Asante-Twi and Ghanaian English. The development of the Ghanaian Digit Triplet Test (GDTT) included initial recording, optimization, and measures of the triplet lists. The evaluation showed high consistency across both languages, with their mean speech recognition thresholds (SRTs) being similar (-11.3 dB for the Asante-Twi, and -11.4 dB for the Ghanaian English, respectively). The statistical characteristics of each language version were comparable to findings from digit triplet tests developed in other languages or dialects. The fourth part of the thesis presents the results of the validation study of the GDTT as a hearing screening tool for Ghanaian adults. Results indicated positive correlations between the Asante-Twi version of the RHHI-S scores and hearing thresholds, as well as a strong correlation between audiometric pure-tone averaged thresholds (PTA) and SRTs obtained by the GDTT. Moreover, the Receiver Operating Characteristics showed a high sensitivity of the GDTT across four cut-off points. Clinically, this implied that the GDTT can serve as an effective screening method for identifying hearing impairment, particularly in settings where traditional audiometric equipment may be limited or inaccessible. Conclusion: This thesis presented and evaluated the first hearing screening material for the Ghanaian adult population, addressing the need for accessible, and culturally friendly tools for early identification of hearing loss. This was accomplished by adapting the RHHI-S into Asante-Twi and developing and validating the Ghanaian Digit Triplet Test (GDTT) in both Asante-Twi and Ghanaian English. The outcome of this research work not only addressed the need for hearing screening materials but also contributed to advancing hearing screening tailored to the linguistic needs of the adult population in Ghana. This study holds promise for promoting the early identification of hearing loss and facilitating access to suitable interventions, ultimately improving the hearing health and overall quality of life for individuals within the Ghanaian population.