Semantic effects in sentence recall: the contribution of immediate vs delayed recall in language assessment

The Effect of Hearing Loss and Working Memory Capacity on Context Use and Reliance on Context in Older Adults

OBJECTIVES

Older adults often complain of difficulty in communicating in noisy environments. Contextual information is considered an important cue for identifying everyday speech. To date, it has not been clear exactly how context use (CU) and reliance on context in older adults are affected by hearing status and cognitive function. The present study examined the effects of semantic context on the performance of speech recognition, recall, perceived listening effort (LE), and noise tolerance, and further explored the impacts of hearing loss and working memory capacity on CU and reliance on context among older adults.

DESIGN

Fifty older adults with normal hearing and 56 older adults with mild-to-moderate hearing loss between the ages of 60 and 95 years participated in this study. A median split of the backward digit span further classified the participants into high working memory (HWM) and low working memory (LWM) capacity groups. Each participant performed high- and low-context Repeat and Recall tests, including a sentence repeat and delayed recall task, subjective assessments of LE, and tolerable time under seven signal to noise ratios (SNRs). CU was calculated as the difference between high- and low-context sentences for each outcome measure. The proportion of context use (PCU) in high-context performance was taken as the reliance on context to explain the degree to which participants relied on context when they repeated and recalled high-context sentences.

RESULTS

Semantic context helps improve the performance of speech recognition and delayed recall, reduces perceived LE, and prolongs noise tolerance in older adults with and without hearing loss. In addition, the adverse effects of hearing loss on the performance of repeat tasks were more pronounced in low context than in high context, whereas the effects on recall tasks and noise tolerance time were more significant in high context than in low context. Compared with other tasks, the CU and PCU in repeat tasks were more affected by listening status and working memory capacity. In the repeat phase, hearing loss increased older adults' reliance on the context of a relatively challenging listening environment, as shown by the fact that when the SNR was 0 and -5 dB, the PCU (repeat) of the hearing loss group was significantly greater than that of the normal-hearing group, whereas there was no significant difference between the two hearing groups under the remaining SNRs. In addition, older adults with LWM had significantly greater CU and PCU in repeat tasks than those with HWM, especially at SNRs with moderate task demands.

CONCLUSIONS

Taken together, semantic context not only improved speech perception intelligibility but also released cognitive resources for memory encoding in older adults. Mild-to-moderate hearing loss and LWM capacity in older adults significantly increased the use and reliance on semantic context, which was also modulated by the level of SNR.

The role of working memory loads on immediate and long-term sentence recall

It is well-established that both phonological and semantic knowledge influence verbal working memory. However, the focus has primarily been on understanding phonological effects despite evidence of semantic influences. Articulatory suppression is a well-established task for preventing phonological processing. Methods to prevent semantic processing have rarely been used in the past, highlighting a need for developing a semantic interference task. We, therefore, conceptualised two novel tasks - an animacy categorisation and semantic relatedness judgement task. This study explored the impact of phonological (articulatory suppression) and semantic loads (animacy categorisation and semantic relatedness judgement) on immediate and delayed sentence recall. Additionally, sentence concreteness (concrete vs. abstract sentences) indexed semantic knowledge in verbal working memory. Across two studies, immediate recall revealed that articulatory suppression (preventing phonological processing) increased the size of the concreteness effect, while the novel semantic tasks (preventing semantic processing) reduced it suggesting that our semantic tasks were indeed imposing a semantic load. Further, relative long-term performance showed that more new words were remembered in articulatory suppression, whereas recall was disproportionately impaired in the semantic relatedness task. Our experimental paradigm offers phonological and semantic suppression tasks that can be used in parallel to investigate the interactions between working memory and language.

The effect of aging on context use and reliance on context in speech: A behavioral experiment with Repeat–Recall Test

Purpose

To elucidate how aging would affect the extent of semantic context use and the reliance on semantic context measured with the Repeat–Recall Test (RRT).

Methods

A younger adult group (YA) aged between 18 and 25 and an older adult group (OA) aged between 50 and 65 were recruited. Participants from both the groups performed RRT: sentence repeat and delayed recall tasks, and subjective listening effort and noise tolerable time, under two noise types and seven signal-to-noise ratios (SNR). Performance–Intensity curves were fitted. The performance in SRT50 and SRT75 was predicted.

Results

For the repeat task, the OA group used more semantic context and relied more on semantic context than the YA group. For the recall task, OA used less semantic context but relied more on context than the YA group. Age did not affect the subjective listening effort but significantly affected noise tolerable time. Participants in both age groups could use more context in SRT75 than SRT50 on four tasks of RRT. Under the same SRT, however, the YA group could use more context in repeat and recall tasks than the OA group.

Conclusion

Age affected the use and reliance of semantic context. Even though the OA group used more context in speech recognition, they failed in speech information maintenance (recall) even with the help of semantic context. The OA group relied more on context while performing repeat and recall tasks. The amount of context used was also influenced by SRT.

Effects of semantic plausibility, syntactic complexity and n-gram frequency on children's sentence repetition

Theories of language processing differ with respect to the role of abstract syntax and semantics vs surface-level lexical co-occurrence (n-gram) frequency. The contribution of each of these factors has been demonstrated in previous studies of children and adults, but none have investigated them jointly. This study evaluated the role of all three factors in a sentence repetition task performed by children aged 4-7 and 11-12 years. It was found that semantic plausibility benefitted performance in both age groups; syntactic complexity disadvantaged the younger group but benefitted the older group; while contrary to previous findings, n-gram frequency did not facilitate, and in a post-hoc analysis even hampered, performance. This new evidence suggests that n-gram frequency effects might be restricted to the highly constrained and frequent n-grams used in previous investigations, and that semantics and morphosyntax play a more powerful role than n-gram frequency, supporting the role of abstract linguistic knowledge in children's sentence processing.

Sentence Recall in Latent and Anomic Aphasia: An Exploratory Study of Semantics and Syntax

We investigated whether semantic plausibility and syntactic complexity affect immediate sentence recall in people with latent and anomic aphasia. To date, these factors have not been explored in these types of aphasia. As with previous studies of sentence recall, we measured accuracy of verbatim recall and uniquely real-time speech measures. The results showed that accuracy did not distinguish performance between latent aphasia and neurotypical controls. However, some of the real-time speech measures distinguished performance between people with latent aphasia and neurotypical controls. There was some evidence, though not pervasive, that semantic plausibility and syntactic complexity influenced recall performance. There were no interactions between semantic plausibility and syntactic complexity. The speed of preparation of responses was slower in latent aphasia than controls; it was also slower in anomic aphasia than both latent and control groups. It appears that processing speed as indexed by temporal speech measures may be differentially compromised in latent and anomic aphasia. However, semantic plausibility and syntactic complexity did not show clear patterns of performance among the groups. Notwithstanding the absence of interactions, we advance an explanation based on conceptual short-term memory as to why semantically implausible sentences are typically more erroneous and possibly also slower in recall.