Normative Data For Nonverbal Memory Tests In A Sample Of Deaf Adults that use French Sign Language

Specific cognitive functioning is described among people with prelingual deafness who use sign language. This would be linked to sensorial deprivation from a premature age and associated with early exposure to sign language leading to a different organization of visuo-attentional and linguistic processes in deaf people, and thus to specific functioning of the nonverbal memory system. Due to a lack of validation, psychometric tests cannot be used to assess cognitive and memory disorders in deaf people who communicate in French Sign Language.

We previously transposed the validated a screening test for cognitive impairment into a version adapted for sign language users: Mini-Mental-State - Langue des Signes (MMS-LS). It takes into account the cultural and linguistic characteristics of this population, providing a useful clinical tool for practitioners. The present study was designed to improve assessment of neurocognitive disorders of deaf individuals by establishing normative values for visual memory tests. Thus, the Rey-Osterrieth Complex Figure and the Doors test from the Doors and People tests were administered to a cohort of 110 deaf signers.

Psychometrics analyses showed excellent inter-rater reliability for copy and reproduction in memory tasks. Both tests exhibited excellent internal validity and were found to be sensitive to the presence of neurocognitive disorders as demonstrated in a group of participants with Major Neurocognitive Disorders and a low MMS-LS score.

Normative values, expressed in percentiles, established from these tests must be interpreted with precaution due to the small number of participants. However, these tools could be made available to neuropsychologists to facilitate clinical use, with further advice on how to better take into account the specificity of this population.