Deficits of Learning in Procedural Memory and Consolidation in Declarative Memory in Adults With Developmental Language Disorder

Abstract

Purpose This study examined procedural and declarative learning and consolidation abilities in adults with developmental language disorder (DLD) relative to their typical language (TD) peers. Method A total of 100 young adults (age 18-24 years) with (n = 21) and without (n = 79) DLD participated across two sites. Performance measures on a recognition memory task and a serial reaction time task were used to assess declarative and procedural memory, respectively. Performance was measured shortly after learning (8 a.m.) and again after a 12-hr, overnight delay (8 a.m.). Results Linear mixed-effects modeling was used to examine the effects of time and group membership on task performance. For the serial reaction time task, there were significant effects of group (TD > DLD) and time (Day 1 > Day 2), but no interaction between them. For the recognition memory task, there was a significant interaction between group and time, driven by overnight gains in the TD group, combined with stable performance across days by those with DLD. Conclusions In procedural memory, adults with DLD demonstrate a learning deficit relative to adults without DLD, but appear to have comparable retention of learned information. In declarative memory, adults with DLD demonstrate a deficit in the overnight enhancement of memory retrieval, despite typical-like learning exhibited when tested shortly after encoding. Supplemental Material https://doi.org/10.23641/asha.13626485.

Figure 1.

Serial reaction time task performance by day by group. Box and whisker plots of serial reaction time (SRT) performance (average reaction time of random trials minus sequence trials) by day by group. Boxes depict second and third quartiles, with the median represented by the horizontal line. Whiskers depict first and fourth quartiles, with outliers represented by single points. DLD = developmental language disorder; TD = typical language.

Figure 2.

Recognition memory task performance by day by group. Boxplots of recognition memory (RM) performance by day by group. Performance is expressed in d' (MacMillan & Creelman, 2004). DLD = developmental language disorder; TD = typical language.