Effects of age on American Sign Language sentence repetition.

This is the authors' abstract. We don't add key points for this paper.

The study of deaf users of signed languages, who often experience delays in primary language acquisition, permits a unique opportunity to examine the effects of aging on the processing of a primary language (L1) acquired under delayed or protracted development. A cohort of 107 congenitally deaf adult signers aged 45–85 years, who were exposed to American Sign Language (ASL) either in infancy, in early childhood, or late childhood were tested using an ASL sentence repetition test. Participants repeated 20 sentences that gradually increased in length and complexity. Logistic mixed effects regression with the factors of Chronological Age and Age of Acquisition was used to assess sentence repetition accuracy. Results showed that Chronological Age was a significant predictor, with increased age being associated with decreased likelihood to reproduce a sentence correctly (OR = 0.56, p = .010). In addition, effects of Age of Acquisition were observed. Relative to native deaf signers, those who acquired ASL in early childhood were less likely to successfully reproduce a sentence (OR = 0.42, p = .003) as were subjects who learned ASL in late childhood (OR = 0.27, p < .001). These data show that aging affects verbatim recall in deaf users of ASL and that the age of sign language acquisition has a significant and lasting effect on repetition ability, even after decades of signed language use. These data show evidence for lifespan continuity of early life effects.