James W. Montgomery

Sentence comprehension in children with specific language impairment: effects of input rate and phonological working memory.

BACKGROUND Many children with specific language impairment (SLI) exhibit sentence comprehension difficulties. In some instances, these difficulties appear to be related to poor linguistic knowledge and, in other instances, to inferior general processing abilities. Two processing deficiencies evidenced by these children include reduced linguistic processing speed and diminished phonological working memory (PWM) capacity. While providing children with SLI a slower input rate appears to facilitate their immediate (real-time) processing of language; it is not known whether such a manipulation might also promote better offline (conventional) sentence comprehension. Complicating the potential benefits of a slower input rate on these childrens offline comprehension is that a slower input rate might negatively interact with their PWM deficit. That is, a slower presentation rate may have the unintended consequence of placing too great a temporal burden on these childrens vulnerable PWM system, thereby leading to even poorer comprehension. That is, a slower input rate presumably requires the listener to store previously processed information for a longer period while new, incoming material is being processed. AIMS To investigate the interaction of input rate and PWM capacity on the sentence comprehension of children with SLI. It was hypothesized that if a slower input rate negatively affects the PWM functioning of children with SLI, these children would comprehend significantly fewer sentences presented at a slower rate versus sentences presented at a normal rate. It was also hypothesized that input rate should have no differential effect on the typically developing control children. METHODS & PROCEDURES A group of 12 school-age children with SLI, a group of 12 age-matched children (CA), and a group of 12 receptive syntax-matched (RS) children (all with normal-range non-verbal IQ and hearing) completed a conventional picture-pointing sentence comprehension task. Sentences were presented at a normal speaking rate and a slower rate (25% time expanded). Children also completed a non-word repetition task, which served as an index of PWM capacity. OUTCOMES & RESULTS Results of the PWM task revealed that the children with SLI repeated fewer three- and four-syllable non-words than both the CA and RS children, suggesting they had reduced PWM capacity. On the sentence comprehension task, a significant group by input rate interaction emerged. The children with SLI yielded significantly poorer comprehension of normal-rate sentences compared with both the CA and RS children. Whereas input rate had no differential effect on CA and RS childrens comprehension, the comprehension of the children with SLI improved to the level of RS children in the slow-rate condition. Correlational analyses showed no significant association between PWM and sentence comprehension in either rate condition for any of the groups. CONCLUSIONS Together, these findings suggest that the simple manipulation of altering speaking rate to children with SLI indeed can facilitate sentence comprehension, with no apparent detrimental effect on the operations of their PWM system.

Relation of auditory attention and complex sentence comprehension in children with specific language impairment: A preliminary study

We investigated the relation of two dimensions of attentional functioning (sustained auditory attention and resource capacity/allocation) and complex sentence comprehension of children with specific language impairment (SLI) and a group of typically developing (TD) children matched for age. Twentysix school-age children with SLI and 26 TD peers completed an auditory continuous performance task (ACPT, measure of sustained attention), a concurrent verbal processing-storage task (measure of resource capacity/allocation), and a picture pointing comprehension task. Correlation analyses were run to determine the association between the measures of attention and sentence comprehension. The SLI group performed more poorly than the TD group across all tasks. For the SLI group, even after removing the effects of age, ACPT score and performance on the concurrent processing-storage task still significantly correlated with complex sentence comprehension. Sustained attention also correlated with simple sentence comprehension. Neither attention variable correlated with sentence comprehension in the TD children. For children with SLI, the comprehension of complex grammar appears to involve significant use of sustained attention and resource capacity/allocation. Even simple sentence comprehension requires significant auditory vigilance. In the case of TD children, neither complex nor simple sentence comprehension appears to invoke significant attentional involvement. Children with specific language impairment (SLI) have special difficulty comprehending complex grammar (Bishop, Bright, James, Bishop, & van der Lely, 2000; Montgomery & Evans, in press; Norbury, Bishop, & Briscoe, 2002; van der Lely, 1996, 1998; van der Lely & Stollwerck, 1997). Many of these same children

Real-time language processing in school-age children with specific language impairment

BACKGROUND School-age children with specific language impairment (SLI) exhibit slower real-time (i.e. immediate) language processing relative to same-age peers and younger, language-matched peers. Results of the few studies that have been done seem to indicate that the slower language processing of children with SLI is due to inefficient higher-order linguistic processing and not to difficulties with more basic acoustic-phonetic processing. However, this claim requires further experimental verification. AIMS It was investigated whether the real-time language processing deficit of children with SLI arises from inferior acoustic-phonetic processing, inefficient linguistic processing, or both poor sensory processing and linguistic processing. If these childrens impaired online language processing is due to inferior acoustic-phonetic processing, then their reaction time (RT) for recognizing words presented in list fashion should be significantly longer relative to control childrens RT. If, however, their impaired language processing relates to inefficient linguistic processing, then, relative to control children, their RT for word-list-presented words should be comparable and their sentence-embedded word-recognition RT should be significantly longer. METHODS & PROCEDURES Sixteen school-age children with SLI, 16 age-matched (CA) typically developing children, and 16 receptive-syntax matched (RS) children completed two word-recognition RT tasks. In one task, children monitored word lists for the occurrence of a target word (isolated lexical processing task). In the second task, children monitored simple sentences for a target word (sentence-embedded lexical processing task). In both tasks, children made a timed response immediately upon recognizing the target. OUTCOMES & RESULTS Children with SLI and CA children showed comparable RT in the isolated lexical processing task and both were faster than RS children. In the sentence-processing task, children with SLI were slower at lexical processing than CA and RS children, with CA children demonstrating the fastest processing. CONCLUSIONS The real-time language processing of children with SLI appears to be attributable to inefficient higher-order linguistic processing operations and not to inferior acoustic-phonetic processing. The slower language processing of children with SLI relative to younger, language-matched children suggests that the language mechanism of children with SLI operates more slowly than what might otherwise be predicted by their linguistic competence.

Children's verbal working memory: Relative importance of storage, general processing speed, and domain-general controlled attention

This study evaluated multiple constraints of verbal working memory in typically developing 7- to 11-year-olds. Multiple measures of verbal working memory and the predictors-short-term memory storage, general speed, and domain-general controlled attention were used. General linear modeling (GLM) showed that storage and the efficiency of controlled attention (i.e., speed of updating information during attention switching) contributed to significant variance in childrens verbal working memory. In a secondary analysis verbal storage and domain-general attention (focus switching accuracy and speed of updating on switch) emerged as significant predictors. Results suggest domain-general attention and verbal storage mechanisms to be independent constraints of verbal working memory.

Role of Auditory Attention in the Real-Time Processing of Simple Grammar by Children with Specific Language Impairment: A Preliminary Investigation.

BACKGROUND This study investigates the effects of two dimensions of attentional functioning, sustained focus of attention and resource capacity/allocation, on the real-time processing of simple sentences by children with specific language impairment (SLI) and typically developing (TD) children matched for age. METHODS & PROCEDURES Thirty-six school-age children with SLI and 36 age-matched TD peers completed an auditory continuous performance task (ACPT) as a measure of sustained attention, a concurrent verbal processing-storage task as a measure of resource capacity/allocation, and a word-recognition reaction time (RT) task (index of sentence processing). Correlation and regression analyses were run to determine the association between the two measures of attention and word recognition RT. OUTCOMES & RESULTS Children with SLI were outperformed by the TD children on each of the tasks. For each group, scores on both the ACPT and concurrent processing-storage tasks significantly correlated with word recognition RT. The partial correlations (with the effects of age removed) remained significant, but only for the SLI group. Results of a regression analysis for the SLI group showed that age predicted 12.3% of unique variance in word recognition RT, while ACPT score accounted for an additional significant 45.7% of unique variance and the processing-storage task score accounted for another significant 4.3% of unique variance. CONCLUSIONS The real-time processing of simple grammar by children with SLI appears to involve significant use of sustained focus of attention and attentional resource capacity. In the case of TD children, however, neither sustained attention nor attentional resources appears to be significantly involved in simple sentence processing.

Role of working memory in children's understanding spoken narrative: A preliminary investigation

The role of phonological short-term memory (PSTM), attentional resource capacity/allocation, and processing speed on childrens spoken narrative comprehension was investigated. Sixty-seven children (6–11 years) completed a digit span task (PSTM), concurrent verbal processing and storage (CPS) task (resource capacity/allocation), auditory–visual reaction time (AVRT) task (processing speed), and the Test of Narrative Language. Correlation and regression analyses examined the association between the memory variables and comprehension. The main findings were (a) CPS and AVRT correlated with comprehension and (b) after accounting for age, CPS accounted for a significant 7.9% of unique variance and AVRT accounted for another significant 5.2%. The results indicate that resource capacity/allocation and processing speed are important to childrens ability to understand spoken narrative.

Relation of three mechanisms of working memory to children’s complex span performance

There is a paucity of research examining the relative contribution of the different mechanisms of working memory (short-term storage [STM], processing speed) to children’s complex memory span. This study served to replicate and extend the few extant studies that have examined the issue. In this study, the relative contribution of three mechanisms of working memory — STM storage, processing speed, attentional resource allocation — to children’s complex span was examined. Children (6—12) completed a digit span task, an auditory-visual reaction time task, a task of attentional allocation, and a complex (listening) span task. Correlation analyses revealed that, after controlling for age, storage, processing speed, and attentional allocation significantly correlated with complex span. Regression analyses showed that, after partialling out age, storage accounted for 12.1% of unique variance in complex span and processing speed accounted for another 6.6% of unique variance; allocation contributed no unique variance. Consistent with the developmental literature, storage and general processing speed play critical roles in children’s complex span performance.

“Whatdunit?” Developmental changes in children's syntactically based sentence interpretation abilities and sensitivity to word order

Aim 1 of this study was to examine the developmental changes in typically developing English-speaking childrens syntactically based sentence interpretation abilities and sensitivity to word order. Aim 2 was to determine the psychometric standing of the novel sentence interpretation task developed for this study, because we wish to use it later with children with specific language impairment. Children listened to semantically implausible sentences in which noun animacy and the natural affordance between the nouns were removed, thus controlling for event probability. Using this novel “whatdunit?” agent selection task, 256 children 7–11 years old listened to two structures with canonical word order and two with noncanonical word order. After each sentence, children selected as quickly as possible the picture of the noun they believed was “doing the action.” Children interpreted sentences with canonical word order with greater accuracy and speed than those with noncanonical word order. Older children (mean age = 10 years, 8 months) were more accurate and faster than younger children (mean age = 8 years, 1 month) across all sentence forms. Both older and younger children demonstrated similar error patterns across sentence type. The “whatdunit?” task also proved to have strong validity and reliability, making it suitable for studies with children with specific language impairment.

Syntactic versus memory accounts of the sentence comprehension deficits of specific language impairment: Looking back, looking ahead

Purpose Compared with same-age typically developing peers, school-age children with specific language impairment (SLI) exhibit significant deficits in spoken sentence comprehension. They also demonstrate a range of memory limitations. Whether these 2 deficit areas are related is unclear. The present review article aims to (a) review 2 main theoretical accounts of SLI sentence comprehension and various studies supporting each and (b) offer a new, broader, more integrated memory-based framework to guide future SLI research, as we believe the available evidence favors a memory-based perspective of SLI comprehension limitations. Method We reviewed the literature on the sentence comprehension abilities of English-speaking children with SLI from 2 theoretical perspectives. Results The sentence comprehension limitations of children with SLI appear to be more fully captured by a memory-based perspective than by a syntax-specific deficit perspective. Conclusions Although a memory-based view appears to be the better account of SLI sentence comprehension deficits, this view requires refinement and expansion. Current memory-based perspectives of adult sentence comprehension, with proper modification, offer SLI investigators new, more integrated memory frameworks within which to study and better understand the sentence comprehension abilities of children with SLI.

Examining the Relative Contribution of Memory Updating, Attention Focus Switching, and Sustained Attention to Children’s Verbal Working Memory Span

Whereas considerable developmental memory research has examined the contributions of short-term memory, processing efficiency, retention duration, and scope of attention to complex memory span, little is known about the influence of controlled attention. The present study investigated the relative influence of three understudied attention mechanisms on the verbal working memory span of school-age children: memory updating; attention focus switching; and sustained attention. Results of general linear modeling revealed that, after controlling for age, only updating accuracy emerged as a significant predictor of verbal working memory span. Memory updating speed (that subsumed attention focus switching speed) also contributed but was mediated by age. The results extend the developmental memory literature by implicating the mechanism of memory updating and developmental improvement in speed of attention focus switching and updating as critical contributors to children’s verbal working memory. Theoretically, the results provide substantively new information about the role of domain-general executive attention in children’s verbal working memory.