Deafness and hard-of-hearing

People with hearing loss can be divided into four categories: the early deaf, the sudden deaf, the late deaf, and the hard-of-hearing. Those with early deafness are generally born deaf or lose their hearing before the age of three. In contrast, people with sudden deafness abruptly lose their hearing within a short amount of time sometime after toddlerhood.

The late deaf also lose their hearing later in life, but this tends to happen gradually over a period of years. People who are hard-of-hearing generally retain some residual hearing, but, similar to the deaf, often experience issues with auditory processing. 

Deafness can be measured and classified:

  • light: 20 – 40 dB
  • moderate: 40 – 60 dB 
  • severe: 60 – 90 dB 
  • profound: > 90 dB

Functional diversity

The community of deaf and hard-of-hearing (DHH) people is incredibly diverse. This holds not only with respect to their development and the extent of their hearing loss, but also to their use of hearing aids, preferences for language and communication, (language) background, education, and their need for support in different life domains. There is, in other words, a great deal of functional diversity. 

DHH people tend to experience limitations in their daily lives to a greater extent than hearing individuals. These constraints are mostly related to the consequences of insufficient access to communication during the developmental years. Such a lack of communication can affect both language learning and cognitive and social-emotional development. In addition, the dominant position of sound and spoken languages in most societies can lead to barriers in social domains, such as education, work, leisure, family life, friendships, and relationships.

In conversation

Kentalis Academy

At Kentalis Academy, we conduct research and develop professional, evidence-based training and applications for care and education in the Netherlands. To this end, we engage in collaboration with our healthcare professionals, educational departments, and advocacy groups of DHH individuals and their parents.

Within the DHH research program, we analyze both personal characteristics and social barriers, and explore the intersectional aspects of being DHH in an environment where sound is the dominant means of communication. In particular, we focus on counteracting the risks associated with the consequences of hearing loss (e.g., developmental problems) and promote the beneficial aspects of being deaf or hard-of-hearing (e.g., identifying with the larger community of DHH people, sign language). We additionally develop evidence-based training modules for parents and professionals to increase the quality of interaction and communication with DHH children and share our insights on creating an inclusive environment with social parties such as schools, sports clubs, employers, and government institutions.  

Teacher classroom teaching sign language

Kentalis International Foundation

At Kentalis International Foundation, we are exclusively focused on deafness and hard-of-hearing knowledge exchange projects with universities, disabled people's organizations, and NGOs in the Global South. Read more about this team here.