Sleep may not benefit learning new phonological categories

Learning and Retention of Novel Words in Musicians and Nonmusicians

Purpose The purpose of this study was to determine whether long-term musical training enhances the ability to perceive and learn new auditory information. Listeners with extensive musical experience were expected to detect, learn, and retain novel words more effectively than participants without musical training. Advantages of musical training were expected to be greater for words learned in multitalker babble compared to quiet. Method Participants consisted of 20 young adult musicians and 20 age-matched nonmusicians, all with normal hearing. In addition to completing word recognition and nonword detection tasks, each participant learned 10 novel words in a rapid word-learning paradigm. All tasks were completed in quiet and in multitalker babble. Next-day retention of the learned words was examined in isolation (recall) and in the context of continuous discourse (detection). Performance was compared across groups and listening conditions. Results Performance was significantly poorer in babble than in quiet on word recognition and nonword detection, but not on word learning, learned-word recall, or learned-word detection. No differences were observed between groups (musicians vs. nonmusicians) on any of the tasks. Conclusions For young normal-hearing adults, auditory experience resulting from long-term music training did not enhance their learning of new auditory information in either favorable (quiet) or unfavorable (babble) listening conditions. This suggests that the formation of semantic and musical representations in memory may be supported by the same underlying auditory processes, such that musical training is simply an extension of an auditory expertise that both musicians and nonmusicians possess.

Sleep Promotes Phonological Learning in Children Across Language and Autism Spectra

Purpose Establishing stable and flexible phonological representations is a key component of language development and one which is thought to vary across children with neurodevelopmental disorders affecting language acquisition. Sleep is understood to support the learning and generalization of new phonological mappings in adults, but this remains to be examined in children. This study therefore explored the time course of phonological learning in childhood and how it varies by structural language and autism symptomatology. Method Seventy-seven 7- to 13-year-old children, 30 with high autism symptomatology, were included in the study; structural language ability varied across the sample. Children learned new phonological mappings based on synthesized speech tokens in the morning; performance was then charted via repetition (without feedback) over 24 hr and followed up 4 weeks later. On the night following learning, children's sleep was monitored with polysomnography. Results A period of sleep but not wake was associated with improvement on the phonological learning task in childhood. Sleep was associated with improved performance for both trained items and novel items. Structural language ability predicted overall task performance, though language ability did not predict degree of change from one session to the next. By contrast, autism symptomatology did not explain task performance. With respect to sleep architecture, rapid eye movement features were associated with greater phonological generalization. Conclusions Children's sleep was associated with improvement in performance on both trained and novel items. Phonological generalization was associated with brain activity during rapid eye movement sleep. This study furthers our understanding of individual differences in the acquisition of new phonological mappings and the role of sleep in this process over childhood. Supplemental Material https://doi.org/10.23641/asha.11126732.

About sleep's role in memory

Over more than a century of research has established the fact that sleep benefits the retention of memory. In this review we aim to comprehensively cover the field of "sleep and memory" research by providing a historical perspective on concepts and a discussion of more recent key findings. Whereas initial theories posed a passive role for sleep enhancing memories by protecting them from interfering stimuli, current theories highlight an active role for sleep in which memories undergo a process of system consolidation during sleep. Whereas older research concentrated on the role of rapid-eye-movement (REM) sleep, recent work has revealed the importance of slow-wave sleep (SWS) for memory consolidation and also enlightened some of the underlying electrophysiological, neurochemical, and genetic mechanisms, as well as developmental aspects in these processes. Specifically, newer findings characterize sleep as a brain state optimizing memory consolidation, in opposition to the waking brain being optimized for encoding of memories. Consolidation originates from reactivation of recently encoded neuronal memory representations, which occur during SWS and transform respective representations for integration into long-term memory. Ensuing REM sleep may stabilize transformed memories. While elaborated with respect to hippocampus-dependent memories, the concept of an active redistribution of memory representations from networks serving as temporary store into long-term stores might hold also for non-hippocampus-dependent memory, and even for nonneuronal, i.e., immunological memories, giving rise to the idea that the offline consolidation of memory during sleep represents a principle of long-term memory formation established in quite different physiological systems.