Reaction Time Performance in Healthy Adults as an Effect of Age and Hand Preference Using the CRTT

Background: The Computerized Revised Token Test (CRTT) is a standardized assessment of language processing abilities. The test requires perceptual, motor, and cognitive skills that may impact patient performance. A battery of reaction time tasks (CRTT-RT) was developed to assess these skills on a more basic, nonlinguistic level in order to assess a patient’s perceptual-motor-cognitive skills’ contribution to their CRTT language performance. Normative data on the CRTT-RT Battery do not currently exist across age and for right and left hands. The purpose of this study was to investigate the effect of age and hand preference on the simple and choice reaction time (RT) tasks included in the CRTT-RT Battery. Procedures: Sixty-four healthy, normal adults completed the CRTT-RT tasks and the CRTT-R-WF version of the CRTT with both their right and left hands. Participants included 32 younger adults (20-32 years; 16 male, 16 female) and 32 older adults (65-78 years; 16 male, 16 female). For this study, the CRTT-RT data were analyzed to evaluate the effects of age and hand preference on speed and accuracy of responses. Results: Statistically significant main effects were determined for both age and hand preference on all RT tasks combined. Age effects were additionally observed on individual RT tasks, where the older group performed slower (increased RT) than the younger group. Hand preference effects were observed on 4 of the 6 RT tasks, those that required motor movement control and response mapping, with the left hand performing significantly slower. A significant interaction between age and hand was observed for CRTT-RT Task 3 (Movement), where the older group demonstrated an over-additive slowing with the left hand. Accuracy of responses on the choice RT tasks demonstrated non-substantive differences between age and hand. Conclusions: Slowing in reaction time performance on the CRTT-RT Battery is evident with increased age as well as non-preferred hand use with a computer mouse. Theories of generalized slowing with age, increased task complexity, cognitive load, and automaticity are explored as potential explanations for the obtained results

Control of Lexical Inhibition in ASL and English-Reading Sentence Comprehension in Deaf and Hearing ASL Users

Background: Language experiences of Deaf individuals are variable and impact cognitive-linguistic functioning. Deaf individuals in the U.S. who use American Sign Language (ASL) as their primary communication method must learn to read and write in English; however they typically exhibit difficulty in doing so due to many factors. Cognitive-linguistic functions, such as inhibition and other executive attentional mechanisms, play a key role in literacy acquisition. One task that measures inhibitory functions is the Stroop task. The Stroop effect has been studied in the Deaf ASL population, however results were inconclusive and studies have focused on the single-word level only. Procedures: This study included 15 hearing non-proficient (HNP), 15 hearing proficient (HP), and 15 Deaf proficient (DP) ASL users. The participants completed an ASL single-word Stroop task, the ASL and English Reading Word Fade versions of the sentence-length Computerized Revised Token Test (CRTT), and the ASL and English Reading Word Fade Stroop versions of the CRTT. Results: No groups demonstrated a reliable Stroop effect for the single-word ASL task, but 10 participants from the DP group did show a Stroop effect on this task. The DP group was the only group to demonstrate a color word Stroop effect on the CRTT ASL Reading Word Fade Stroop task. All groups demonstrated a significant Stroop effect for the English Reading Word Fade Stroop task. The DP group demonstrated larger interference in English than the hearing groups, and produced lower Mean-CRTT scores across both languages. Language proficiency did not predict a Stroop effect for any group for either language, however, individuals that were more language proficient were faster to respond to the sentence-level stimuli than the less proficient. Conclusions: The DP group demonstrated lexical processing in both ASL and English at the sentence level, evidenced by observable Stroop effects, however the magnitude of the effects suggest reduced inhibitory control or slow lexical activation observed in the bilingual (ASL-English) population. At the single-word level, individual participant factors influenced the presence of a Stroop effect. The DP group was slower to read words in all tasks across both languages, suggesting requirement for additional processing time

A comparison of left versus right hand, and mouse versus touchscreen access methods on the Computerized Revised Token Test

This study examined the effect of hand used to access mouse vs. touchscreen in both normal adult individuals (NAI) and persons with aphasia (PWA) on the overall score from the Computerized Revised Token Test (CRTT) (McNeil et al., 2008). Both access modes were highly correlated with each other in both groups. PWA performed significantly worse than the NAI on both access modes, regardless of hand used. The touchscreen access mode generated significantly higher scores than the mouse for both groups independent of hand. The correlation coefficients within hand and between access modes were significant and high for both groups

Effects of signal intensity level and noise-simulated hearing loss on auditory language processing persons with aphasia

This study assessed the role of presentation level and high-frequency audibility in auditory processing of participants with aphasia (PWA). Performance of PWA was compared to non-brain-injured participants (NBIP) on the Computerized Revised Token Test (C-RTT) at varying signal intensity levels, and under normal and simulated hearing loss conditions. The PWA performed significantly more poorly than the NBIP under both conditions. Maximum performance required significantly higher presentation levels in the simulated hearing loss condition than in quiet; with similar gain and level requirements were observed for both groups. The results will be discussed relative to auditory language processing in PWA

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

The current study investigated whether persons with aphasia (PWA) exhibit longer processing times than normal adult individuals (NAI) in conditions that require more complex linguistic integration, using a self-paced word-by-word sentence reading method. The word-category comparison revealed that PWA show significantly longer reading times for nouns with high integration cost than for determiners with least linguistic integration cost compared to NAI. These results are consistent with the findings that PWA exhibit language-processing difficulties at points of high processing demand (Caplan, et al., 1985; McNeil, 1982)

Developing a standardized measure of short-term memory and syntactic complexity: results from subtests of the CRTT-R

Short-term memory (STM) effects have shown to be distinguishable from other working memory components supporting complex computations/central executive functions. To develop a measure capable of assessing the effects of STM and linguistic computations on sentence processing,  effects of syntactic complexity and padding were investigated with the Computerized Revised Token Test –Revised in individuals with aphasia and control participants.  Off-line measures revealed clear effects of both factors.  The expected interaction of complexity and padding  and overadditive effects for individuals with aphasia were not found. An effect of complexity on word errors in passive sentences for individuals was shown

Test-retest reliability of the auditory Computerized Revised Token Test (CRTT) and three experimental reading CRTT-R versions in normal elderly individuals and persons with aphasia

The purpose of this study was to assess the test-retest reliability of the Computerized Revised Token Test (CRTT) and three CRTT-R reading versions in normal elderly individuals (NEI) and in persons with aphasia (PWA). Results revealed high correlation coefficients between test and retest performance for all CRTT versions in the PWA and moderate to high correlations in the NEI. There were no significant differences among test-retest conditions for overall and subtest scores except for the reading word-fade condition (both groups) and auditory condition for the PWA. Overall, high test-retest reliability of the CRTT and the three CRTT-R versions was demonstrated

Impact of Speaking Styles on the Accuracy of Predicted Speech Intelligibility

Conversational speech used in research studies is not true conversational speech that individuals use in day-to-day communication. Laboratory-created speech materials are read or memorized and repeated and have different acoustic characteristic compared to true conversational speech. It is of interest to investigate how speaking styles (clear speech, lab conversational speech, and natural conversational speech) impact actual (measured) and predicted speech intelligibility in young adults with normal hearing. Two experiments were conducted in the current study. Speech stimuli were created using the contents of the Story Retelling Procedure (SRP) (Doyle et al., 2000; McNeil et al., 2007) produced by a male talker to create stimuli for each of the three speaking styles. Speech recordings were rated by thirty individuals with normal hearing based on how natural speech sounded. There was a strong, positive correlation between the speech recordings and how listeners perceived the naturalness of speaking styles therefore allowing comparison of materials considered clear speech, lab conversational speech, and natural conversational speech. Experiment 1 was designed to investigate if there was any significant difference among speech intelligibility for clear, laboratory conversational, and natural conversational speech in five listening conditions (quiet, +3, 0, -3, and -6 dB SNR). The dependent variable (DV) was proportion correct of identified keywords (i.e., speech intelligibility). The results showed that speaking styles and listening conditions impact measured speech intelligibility. Specifically, there were significant differences in the speech intelligibility between lab conversational speech and natural conversational speech. Moreover, the clear speech speaking style can be used to improve listening performance in challenging listening conditions. Experiment 2 was designed to investigate if the STMI model can accurately predict speech intelligibility for different speaking styles and to evaluate the overall ability of the STMI model to capture speech intelligibility in multi-talker babble noise conditions. The results demonstrated that the current version of the STMI may not be sensitive enough to predict speech intelligibility for different speaking styles when embedded into multi-talker babble