Neil Szuminsky

Verbal working memory and its relationship to sentence‐level reading and listening comprehension in persons with aphasia

Background: Working memory (WM) has gained recent attention as a cognitive construct that may account for language comprehension deficits in persons with aphasia (PWA) (Caspari, Parkinson, LaPointe, & Katz, 1998; Martin, Kohen, & Kalinyak‐Fliszar, 2008; Wright, Downey, Gravier, Love, & Shapiro, 2007). However, few studies have investigated individual differences in performance on sentence comprehension tasks as a function of WM capacity in PWA when WM demands are manipulated. Aims: The purposes of the current study were: (1) to examine the relationships among verbal WM, sentence comprehension, and severity of impairment in PWA and (2) to investigate the differential performance of high versus low verbal WM groups on sentence comprehension tasks in which task demands were manipulated by the length of the sentence stimuli, complexity of syntactic structure, and by presentation method which varied the time over which the linguistic material was available for computation. Methods & Procedures: A total of 20 PWA were divided into high and low WM groups based on a listening version of a WM sentence span task. Each participant completed a listening version (CRTT) and three reading versions (CRTT‐R) of the Computerised Revised Token Test as the sentence comprehension tasks. Outcomes & Results: The WM task significantly predicted performance on the CRTT conditions in which information was only temporarily available, thereby imposing greater WM demands on sentence comprehension. The verbal WM task was significantly correlated with aphasia severity and a principal components analysis revealed that the WM task, overall aphasia severity, and overall reading impairment level loaded on a single factor with 76% of shared variance. The low WM groups performance was significantly lower than the high WM group on the CRTT subtests with syntactically more complex structures and on the CRTT conditions with temporally restricted presentation methods. Conclusions: This verbal WM task was significantly and moderately correlated with the overall severity of aphasia as well as with both listening and reading sentence comprehension. The WM group differences emerged only in sentence comprehension tasks with greater WM demands. These results are consistent with the notion that WM effects are most evident when WM capacity is sufficiently taxed by the task demands (e.g., Caplan & Waters, 1999; Just & Carpenter, 1992).

Effects of Online Augmented Kinematic and Perceptual Feedback on Treatment of Speech Movements in Apraxia of Speech

Apraxia of speech (AOS) is a motor speech disorder characterized by disturbed spatial and temporal parameters of movement. Research on motor learning suggests that augmented feedback may provide a beneficial effect for training movement. This study examined the effects of the presence and frequency of online augmented visual kinematic feedback (AVKF) and clinician-provided perceptual feedback on speech accuracy in 2 adults with acquired AOS. Within a single-subject multiple-baseline design, AVKF was provided using electromagnetic midsagittal articulography (EMA) in 2 feedback conditions (50 or 100%). Articulator placement was specified for speech motor targets (SMTs). Treated and baselined SMTs were in the initial or final position of single-syllable words, in varying consonant-vowel or vowel-consonant contexts. SMTs were selected based on each participant’s pre-assessed erred productions. Productions were digitally recorded and online perceptual judgments of accuracy (including segment and intersegment distortions) were made. Inter- and intra-judge reliability for perceptual accuracy was high. Results measured by visual inspection and effect size revealed positive acquisition and generalization effects for both participants. Generalization occurred across vowel contexts and to untreated probes. Results of the frequency manipulation were confounded by presentation order. Maintenance of learned and generalized effects were demonstrated for 1 participant. These data provide support for the role of augmented feedback in treating speech movements that result in perceptually accurate speech production. Future investigations will explore the independent contributions of each feedback type (i.e. kinematic and perceptual) in producing efficient and effective training of SMTs in persons with AOS.

Reliability and Validity of the Computerized Revised Token Test: Comparison of Reading and Listening Versions in Persons With and Without Aphasia

PURPOSE This study assessed the reliability and validity of intermodality associations and differences in persons with aphasia (PWA) and healthy controls (HC) on a computerized listening and 3 reading versions of the Revised Token Test (RTT; McNeil & Prescott, 1978). METHOD Thirty PWA and 30 HC completed the test versions, including a complete replication. Reading versions varied according to stimulus presentation method: (a) full-sentence presentation, (b) self-paced word-by-word full-sentence construction, and (c) self-paced word-by-word presentation with each word removed with the onset of the next word. Participants also received tests of aphasia and reading severity. RESULTS The listening version produced higher overall mean scores than each of the reading versions. Differences were small and within 1 standard error of measurement of each version. Overall score test-retest reliability among versions for PWA ranged from r=.89 to r=.97. Correlations between the listening and reading versions ranged from r=.79 to r=.85. All versions correlated highly with aphasia and reading severity. Correlations were generally low for the HC due to restricted variability. Factor analysis yielded a 2-factor solution for PWA and a single-factor for HC. CONCLUSIONS Intermodality differences were small, and all 4 versions were reliable, concurrently valid, and sensitive to similar linguistic processing difficulties in PWA.

Effects of perturbation and prosody on the coordination of speech and gesture

The temporal alignment of speech and gesture is widely acknowledged as primary evidence of the integration of spoken language and gesture systems. Yet there is a disconnect between the lack of experimental research on the variables that affect the temporal relationship of speech and gesture and the overwhelming acceptance that speech and gesture are temporally coordinated. Furthermore, the mechanism of the temporal coordination of speech and gesture is poorly represented. Recent experimental research suggests that gestures overlap prosodically prominent points in the speech stream, though the effects of other variables such as perturbation of speech are not yet studied in a controlled paradigm. The purpose of the present investigation was to further investigate the mechanism of this interaction according to a dynamic systems framework. Fifteen typical young adults completed a task that elicited the production of contrastive prosodic stress on different syllable positions with and without delayed auditory feedback while pointing to corresponding pictures. The coordination of deictic gestures and spoken language was examined as a function of perturbation, prosody, and position of the target syllable. Results indicated that the temporal parameters of gesture were affected by all three variables. The findings suggest that speech and gesture may be coordinated due to internal pulse-based temporal entrainment of the two motor systems.

Real-time Processing in Reading Sentence Comprehension for Normal Adult Individuals and Persons with Aphasia

Background: Persons with aphasia (PWA) have shown difficulties in integrating linguistic materials over time and distance in sentence processing. However, few studies have investigated sentence-processing difficulties among PWA as reflected in online processing measures. Furthermore, relatively few studies have examined the online processing of syntactically simple but computationally demanding sentences among PWA. Such sentences are important from the perspective of resource-related theories of aphasic language deficits, which predict that such sentences should be challenging for PWA even if the syntactic structures involved are not. Aims: The purpose of the study was to investigate the sentence-level online reading times of normal adult individuals (NAI) and PWA by word category and as a function of adjective padding. It was assumed that head nouns entail greater processing costs than determiners because they represent the point at which integration of material within a noun phrase must take place. It was also assumed that increasing adjectival padding within a noun phrase requires more integration and creates greater processing costs. Methods & Procedures: A total of 30 NAI and 30 PWA participated in the current study. Sentence stimuli were obtained from the Computerised Revised Token Test (CRTT) (McNeil et al., 2008). Sentences were presented using a non-cumulative (Word Fade = WF) self-paced word-by-word reading method (CRTT-R-WF). Reading times for the determiners and the correct nouns were analysed. Outcomes & Results: Both groups showed significantly longer reading times for the nouns than for determiners and in two-adjective than in one-adjective conditions. Furthermore, the reading times for the two-adjective condition were significantly longer than the one-adjective condition for nouns but not determiners across the groups. The PWA exhibited significantly longer overall reading times, as well as significantly longer reading times on the nouns than the NAI. Conclusions: Increased linguistic integration costs—imposed by greater amounts of material to be integrated, and appearing at the point where integration must take place—differentiated reading-time performance between the NAI and PWA participant groups. The PWA showed differentially longer online processing times for elements that imposed high integration costs. This difference appeared most dramatically when two adjectives intervened between the determiner and the head noun. The current results are consistent with resource-related hypotheses regarding aphasic language deficits, which suggest that PWA with limited control of processing resources should show differentially greater impairments in sentence processing as compared to NAI.

Motor learning of volitional nonspeech oral movements: Intraoral pressure and articulatory kinematics

This study provides initial validation of a complex nonspeech task that will be used in future research for examining and comparing the neurophysiologic mechanisms of speech and volitional nonspeech oral movements. Motor learning of a complex sequence of lip, jaw, and tongue movements was explored as speakers produced one of three intraoral air‐pressure targets during each bilabial closing gesture in the sequence. Motor learning was demonstrated by retention of pressure targets subsequent to acquisition. Transfer to other nonspeech tasks was also explored, as were changes in articulatory kinematics with learning. The current nonspeech task was constructed to parallel speech production, by controlling several commonly observed physiologic characteristics of speech (i.e., complex sequence of potentially overlapping articulatory segments; goal of intraoral pressure during bilabial closure). This construction of the nonspeech task, along with its demonstrated motor learning, greatly extends the ability to mak...