Access to appropriate hearing health care can be difficult for some segments of the population in a high-income context,1 so it should come as little surprise that for those residing in low- and middle-income countries (LMICs), access to such services can be nearly impossible. The scale of the problem becomes even more apparent when considering that approximately 80 percent of those with significant hearing loss reside in LMICs.2
With a plethora of competing health priorities in LMICs, hearing loss may become a less pressing concern for overstretched health care services, leading to a lack of public funding.3 Lack of trained hearing health care professionals and facilities, particularly outside of major urban areas, also hinders access. Even when private hearing health care is available, poverty may prevent many of those in need from obtaining services. The unmet need for hearing habilitation or rehabilitation services in these areas is thus very great.4
A range of philanthropic organizations have attempted to reduce the disease burden in these regions.5-9 We conducted research to investigate this question: Are we currently maximizing the benefit of these efforts, and if not, how could we better meet the needs of those with significant hearing loss in LMICs?10
EVALUATING DONATION PROGRAMS
We evaluated the objective and subjective outcomes of two large-scale hearing aid donation programs in the Philippines as a way of understanding the benefits and limitations of such programs. Patients in both programs had been fitted with basic analogue hearing devices with little or no frequency shaping available and stock ear coupling. The donation programs utilized a non-standard, group-based fitting and instruction format, with participants moving through various stations on their way to completion.10 In the first program, 101 participants were sampled at the time of fitting and assessed via real ear measurement. In the second program, 153 participants were sampled six months after receiving a hearing aid. The second group was assessed with real ear measurement, performance measures, and the International Outcome Inventory for Hearing Aids (IOI-HA). Participants sampled in both programs had, on average, severe-to-profound bilateral hearing loss.
The first key finding of the study was that subjective outcomes (as reported on the IOI-HA) were essentially equivalent to those seen in a range of other studies, many of which took a more conventional approach to hearing aid fitting and with higher-quality devices.11-16 The only deviation from this was that device usage was lower than in previously reported studies.
The second key finding was that devices were rarely fit close to the insertion gain target, even when using the most generous possible criteria (Fig. 1). Fit-to-target was increasingly poor as hearing threshold increased. Interestingly, no statistical relationship was seen between four frequency average fit-to-target and IOI-HA total scores.
The third key finding was that performance measures and questions on the practical use of the hearing devices indicated that participants had significant device management problems. Participants reported difficulty inserting devices, feedback, and poor device comfort in the ear and in noisy conditions (Table 1).
It would be naïve to expect that large-scale hearing aid philanthropic donation programs would achieve outcomes equivalent to those seen in standard clinical fittings in high-income countries. It was therefore somewhat surprising to find such positive subjective outcomes in our study population, particularly in light of the poor objective outcomes. This apparent inconsistency can likely largely be explained by a cultural and contextual response bias, perhaps best expressed by the Filipino phrase “utang na loob,” which roughly translates into “debt of gratitude.”17 It seems likely that the subjective responses reflect a positive bias in the report of benefit, driven by a wish to seem grateful for the services provided.
The poor fit-to-insertion gain targets in the programs sampled point to problems with one or more of the following: population targeting, device suitability, and fitting/delivery method.
The World Health Organization (WHO) recommends a focus on aiding individuals with moderate to severe loss.4 Although excluding those with profound hearing loss may seem counterintuitive since they appear to be the most in need of assistance, this population may in fact receive very little benefit from a hearing aid.18 This is particularly the case among older children or adults with prelingual hearing impairment or those deprived of auditory stimulus over long time periods.19-21 The poorer fit-to-target seen in those with poorer hearing thresholds in this study highlights the importance of carefully considering the potential benefits of fitting those with profound hearing loss. Better targeting of donation populations will likely maximize the benefits and minimize false hopes, which might be instilled in those who could otherwise be encouraged to engage with signing programs.
Device quality was likely a significant factor that limited optimal objective outcomes. To reduce costs and deliver services to as many individuals as possible, it is to be expected that devices fitted in philanthropic programs will be less sophisticated than those in high-income contexts. To guide those delivering services in developing countries, the WHO has developed a set of basic hearing aid requirements for such contexts.4 Particularly relevant here are the suggestions that frequency shaping of at least some degree be included and that custom earmolds are preferred over stock ear coupling options. We would add that the latter suggestion could be relaxed somewhat if feedback reduction systems were present. Low-cost devices that meet these specifications and are designed for use in LMICs can be found in the market.22 Obtaining locally produced low-cost earmolds can be difficult in many LMICs. However, successful efforts in developing local capacity for earmold production have been demonstrated in LMIC contexts.23 The problems with fit-to-target, comfort, and feedback seen in the evaluated programs could be largely alleviated with the consideration of these suggestions.
Fitting or delivery method may have contributed to the poor objective outcomes in this study. The programs evaluated here required the fitting of large numbers of individuals in very short time frames that necessitated the use of a non-standard group-based fitting approach. While some research suggests that elements of a group-based approach can be supported, more research is needed to ensure that maximum efficiency can be achieved with minimal loss of effectiveness.24 Indeed, such efforts have been previously described and continue to be an area of interest for our research group.25
When considering the planning and implementation of a philanthropic health program, it is important to take into account the more philosophical debate surrounding the relative benefits of horizontal and vertical strategies of intervention.26 Horizontal interventions typically aim to build or scaffold local health service capacity, have a longer-term focus, and have a broad range of services delivered. Vertical approaches tend to be narrower in scope, usually focusing on one health condition with a limited number of intervention strategies utilized, and are often larger in scale. A horizontal approach would seem to suit hearing rehabilitation well, considering that hearing loss is often a chronic condition requiring lifetime care. The programs evaluated in our paper were of a more vertical nature, a strategy more suited to short-term health emergencies. Both types of intervention have their place, and combined or diagonal approaches are also possible to capture the benefits of both intervention types.26 The difficulties with hearing aid management described in this research (Table 1) point to the potential limitations that can be encountered in vertical programs when a structured plan for follow-up care is not in place.
What effect might recent developments in telehealth, low-cost diagnostic equipment, and over-the-counter or self-fitted hearing devices have on hearing health philanthropy? Efforts aimed at remotely supporting local community health workers have been shown to be effective and offer the potential to overcome some of the tyranny of distance.27 Relatively low-cost diagnostic equipment with self-testing options offers pathways for patient screening and reduces the cost of equipping local audiology clinics.28 Over-the-counter or self-fitted hearing devices may play a role in addressing the needs of those in LMICs, but are at present more suitable for those with milder forms of hearing loss.29 With the required focus on moderate to severe losses, such devices will not play a significant role, at least in the near future, and do not obviate the need for local assistance and follow-up care.30
This discussion does not seek to disparage or discourage hearing health philanthropy, but rather to attempt to identify areas of weakness in the current service delivery and point the way to improved outcomes for future programs.
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