PROJECT SUMMARY
Developmental language disorder (DLD) describes the idiopathic disorder(s) of language that occurs in
approximately 7% of the population. Although DLD is understudied in adulthood, it is clear that the
communication challenges in DLD extend beyond adolescence. The barriers to educational and vocational
achievement for adults with DLD include persistent difficulties in learning and memory. Recent work suggests
that these difficulties with learning and memory include deficits in overnight memory consolidation. Thus, an
effective support for learning and memory function in adults with DLD must include strategies for both
overcoming initial challenges in learning, as well as in mitigating a deficit in consolidation of learned
information. In this project, we combine insights from the neurobiology of learning and memory, chronobiology,
and speech perception, to determine the optimal training schedule for perceptual memory retention in
adults with and without DLD. We have two Aims in this project: First, we will recruit 240 adults (120 with/120
without DLD) to participate in a speech-perceptual training to take place in one of six different training
schedules over 24 hours. We predict that our manipulation of training schedules will interact with circadian
preference and timing relative to overnight consolidation, such that we may discover the optimal practice
schedule for speech sound retention for adult learners with & without DLD. Our focus on speech-sound
information will allow us to track the learning and memory of linguistic form that is relatively independent from
preexisting knowledge; moreover, speech perception is also a known difficulty for individuals with DLD. Under
our second aim, we will recruit an additional 300 adults (150 with/150 without DLD) in order to determine how
optimal training schedules interact with reflexive and reflective learning strategies in adults with and without
DLD. We will achieve this aim by tracking the time course of learning and retention in adults participating in
reflexive and reflective categorization training in one of six training schedules. This will provide us with
generalizable insights into optimal training schedules for learning targets beyond the speech domain. The
knowledge to be gained from this work will contribute to the basic science of learning and memory in adults
with and without DLD. In addition, the factors that influence the successful retention of speech have substantial
implications for intervention practices for other developmental disorders in which speech representations are
implicated (speech sound disorder, dyslexia).
