Communication barriers to dental care for deaf and hard-of-hearing children: a cross-sectional survey of guardians in Bangkok, Thailand

Technical Summary: Communication Barriers to Dental Care for Deaf and Hard-of-Hearing Children in Bangkok

Problem Statement
Deaf and hard-of-hearing (DHH) individuals globally report poorer oral health outcomes and frequent communication difficulties during dental care compared to their hearing peers. While existing literature from high-income, English-speaking settings identifies communication as a primary determinant of access gaps, there is a scarcity of quantitative data regarding these barriers within the Thai context. Specifically, it remains unknown how communication barriers manifest in Thai dental care for DHH children, which demographic or clinical subgroups are most affected, and how these barriers interact with the Universal Coverage Scheme (UCS) entitlements. This study addresses the gap in understanding the content and distribution of these barriers to inform the design of equitable oral health services in Thailand.

Methodology
The study employed a cross-sectional survey design conducted between December 2017 and January 2018.

• Population: The sample consisted of guardians of all pupils enrolled in the two principal schools for the deaf in Bangkok: Setsatian School for the Deaf and Thungmahamek School for the Deaf. The total eligible population was 278 families; 262 usable questionnaires were returned (96.8% response rate).
• Instrument: A structured questionnaire was developed based on classroom observations, interviews with teachers/guardians, and national oral health survey data. It comprised four sections: guardian demographics, child demographics (including hearing status and severity), dental service access patterns, and communication experiences.
• Primary Outcome: A closed-item question asking whether a communication barrier occurred during the child's dental care (Yes/No). Guardians reporting a barrier provided open-ended descriptions.
• Analysis:
  • Quantitative: Descriptive statistics, chi-square tests (and Fisher's exact tests for small cell counts), and multivariable logistic regression were used to test associations between barriers and socio-demographic/clinical characteristics.
  • Qualitative: Open-ended responses (63 descriptions yielding 81 coded mentions) underwent independent double-coding by two authors using qualitative content analysis. Inter-rater reliability was substantial (Cohen's κ = 0.73).
  • Exploratory: Post-hoc analyses examined patterns of service use, awareness of UCS entitlements, and guardian attitudes.

Key Results

• Prevalence of Barriers: Among the 171 guardians who answered the barrier item (representing children with dental care experience), 48.5% (83 individuals) reported at least one communication barrier.
• Nature of Barriers: Qualitative content analysis identified four primary themes, with provider-side sign-language incapacity being the dominant theme (29 mentions, 28.6% of coded mentions).
  • Provider Incapacity: The most frequent specific issue was dental personnel not knowing sign language, preventing direct communication.
  • Exchange Breakdown: Failures in mutual understanding between dentist and child (14.3%) and child and dentist (11.1%).
  • Child Limitations: Inability of the child to express symptoms (12.7%).
  • Family Limitations: Guardians' own inability to sign fluently enough to bridge the gap (20.6%).
  • Interpreter Availability: Professional interpreters were rarely used (9.4%–13.6% of visits); communication was largely mediated by accompanying persons, who often spoke entirely on the child's behalf (36.5%).
• Determinants of Barriers: No guardian characteristic (education, income, relationship) or child characteristic (sex, congenital status, additional disability, hearing aid use) was independently associated with reporting a barrier in the multivariable logistic regression model. While an unadjusted association existed with hearing loss severity, it was not significant after clinically meaningful categorization or multivariable adjustment.
• Service Use and Awareness:
  • Care was predominantly symptom-driven (46.5%); only 20.1% attended routinely.
  • Awareness of UCS entitlements was low: 68.0% of guardians did not know where the child's coverage could be used.
  • Unawareness of entitlements was significantly associated with never having visited a dentist (12.9% vs. 1.5% for aware guardians, p=0.009).
  • 94.5% of guardians stated they would seek more care if informed about entitlements.
• Guardian Attitudes: Guardians who reported barriers were significantly more likely to prefer facilities with sign-language-capable dentists or interpreters (Crude ORs ranging from 2.5 to 3.5).

Key Contributions

1. Empirical Evidence in Thailand: This study provides the first quantitative data on communication barriers to dental care for DHH children in Thailand, moving beyond anecdotal evidence or studies focused on non-dental settings.
2. Systemic vs. Individual Determinants: The findings challenge the assumption that barriers are driven by family characteristics (e.g., income, education) or the severity of the child's impairment. Instead, the data suggests the gap lies primarily in provider and service capacity, specifically the lack of sign language competence among dental personnel and the absence of professional interpreters.
3. Identification of Informational Barriers: The study highlights that lack of awareness regarding universal coverage entitlements is a critical upstream barrier, preventing initial access to care for a significant portion of the population.
4. Qualitative Insight: The content analysis reveals that the "mechanics of shared language" (specifically the inability of dentists to sign) is the overwhelming obstacle, leading to the bypassing of the child's voice in clinical interactions.

Significance and Claims
The authors claim that communication barriers affect approximately half of DHH children who have received dental care in this population. The study posits that the primary solution lies not in targeting specific high-risk subgroups of families or children, but in systemic improvements to the dental workforce and service delivery.

The paper concludes that priorities for advancing equity include:

• Building foundational sign-language competence within the dental workforce (including reception staff).
• Ensuring the reliable availability of qualified sign-language interpreters.
• Developing signed digital tools adapted to Thai Sign Language.
• Improving information dissemination regarding universal coverage entitlements through schools to convert latent demand into actual care utilization.

The authors maintain a modest stance, acknowledging that their observational data identifies priorities rather than proving intervention effectiveness. They note limitations regarding the reliance on guardian reports rather than direct observation, the urban school-based sample, and the cross-sectional design which precludes causal inference. However, they argue that the convergence of barrier content, lack of subgroup associations, and guardian preferences strongly points to provider capacity and information access as the critical levers for change.