Sickle cell disease (SCD) is known to be associated with a higher prevalence of sensorineural hearing loss (SNHL) and poor school performance compared to hemoglobin AA carriers, increasing the risk for cognitive impairment in these patients. Nonetheless, hearing impairment in the absence of SCD is also negatively associated with learning-related cognitive functions, leaving the association between SCD and hearing deficits, school performance, and cognitive function not yet fully understood.

A cross-sectional study published by Fontes Barros Bomfim and colleagues in Tropical Medicine & International Health investigated all 3 factors in 31 participants diagnosed with SCD and 31 participants with hemoglobin AA aged between 8 and 18 years of both sexes. 

Audiometry, immitanciometry, and application of the Scale of Auditory Behaviors (SAB) questionnaire determined hearing impairment. A version of the Mini-Mental State Examination (MMSE) adapted for children screened the risk of cognitive function impairment. An interview conducted with the parents determined academic school performance, then classified as good, regular, or poor.

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SNHL, although mild, was present in 25.8% of children with SCD and only 3.2% in the control group. Poor school performance also showed higher occurrence in the SCD group, with 25.8%, vs 6.5% in the control group, and 62.5% of children with SCD and SNHL had poor school performance. Likewise, the SCD group scored lower in almost all evaluating parameters of the MMSE, specifically attention and calculation, although excluding language and immediate memory. Among the SCD participants, MMSE and SAB scores were similar regardless of the presence of SNHL.

Coherently, the authors found that of all children with SNHL in both the SCD and control groups, 100% had vaso-occlusive episodes in the last 12 months. These findings are consistent with previous reports where patients with SCD exhibit impaired academic performance, primarily associated with recurrent hospitalizations and hence school absenteeism. Moreover, central auditory processing is known to play a key role in language and learning, and silent cerebral infarctions are a proposed cause of SNHL and a decrease in other cognitive abilities evaluated in the MMSE in children with SCD.

Behavioral deficits have been identified in otherwise healthy children with SNHL, “therefore, it is possible that SNHL may influence academic performance and be associated with the aggravation of cognitive impairment already arising from SCD,” the authors wrote.

Finally, while parental education and socioeconomic status also influence cognitive function in children, this study decreased such interfering factors by including healthy siblings and cousins of the SCD patients in the control group.

The study concluded that “hearing impairment in children and adolescents with SCD, specifically SNHL, is associated with poor school performance and enhances the risk of cognitive impairment in terms of attention and calculation.”

Reference

Fontes Barros Bomfim JR, Orge Anunciação Bacelar C, Marques da Silva Neto M, Salles C, Marice Teixeira Ladeia A, Renata Rissatto‐Lago M. Association between hearing impairment, school performance and cognitive function in children and adolescents with sickle cell diseaseTrop Med Int Health. Published online January 19, 2022. doi:10.1111/tmi.13722