Voice Reaction Time Research Articles

Identifying task-general effects of stimulus familiarity in the parietal memory network

Studies of human memory have implicated a “parietal memory network” in the recognition of familiar stimuli. However, the automatic vs. top-down nature of information processing within this network is not yet understood. If the network processes stimuli automatically, one can expect repetition-related changes both when familiarity is central to an ongoing task and when it is task-irrelevant. Here, we tested this prediction in a group of 40 human subjects using fMRI. Subjects initially named 100 objects aloud in the scanner. They then repeated the same task with novel and previously-named objects intermixed (where familiarity was not task-relevant) and separately were asked to make old/new recognition decisions in response to pictures of novel and previously-named objects (where familiarity was central to task completion). Accuracy was matched across conditions, and voice reaction times reflected typical behavioral priming effects. Repetition enhancement effects were restricted primarily to parietal cortex—and in particular, the parietal memory network—and were task-general in nature, whereas repetition suppression effects were task-dependent and occurred primarily in frontal and ventral temporal cortex. Task context effects were also present in the parietal memory network and impacted responses to both novel and familiar items. We conclude by discussing implications of these findings with respect to current hypotheses regarding parietal contributions to memory retrieval.

C-PLACID - Computational PLatform for Assessment of Cognition In Dementia - EPSRC

C-PLACID - Computational PLatform for Assessment of Cognition In Dementia - EPSRC

The effects of aging on the attentional demands of walking toward and stepping up onto a curb

Community ambulation requires the capacity to alter gait in response to obstacles within the path of travel that appear at a known location. Acquiring information from the environment to safely negotiate a curb may increase the cognitive demands of walking. The purpose of this study was to examine the attentional demands of walking toward and stepping up onto a curb in young, middle-age and older adults. Single and dual-task voice reaction time (VRT) was measured in community-dwelling young (n=24), middle-age (n=24), and older adults (n=24) across 5 conditions: sitting in a chair, standing, level walking, and walking toward and while stepping up onto a curb. A 3 (group) by 5 (task condition) ANOVA was used to examine VRT. The interaction of group with task revealed statistically significant within group increases in VRT when comparing either sitting and/or standing to walking on a level surface and walking toward the curb and stepping up onto the curb. When compared to the other groups, older adults had significantly longer VRT for all walking tasks. Stepping onto the curb significantly increased the attentional requirements of walking for all of the groups when compared to level walking. The pattern of statistically significant between group and within group differences during the walking tasks indicate the effects of a curb located at a predictable place in the environment on attentional allocation.

Use of mobility aids reduces attentional demand in challenging walking conditions

While mobility aids (e.g., four-wheeled walkers) are designed to facilitate walking and prevent falls in individuals with gait and balance impairments, there is evidence indicating that walkers may increase attentional demands during walking. We propose that walkers may reduce attentional demands under conditions that challenge balance control. This study investigated the effect of walker use on walking performance and attentional demand under a challenged walking condition. Young healthy subjects walked along a straight pathway, or a narrow beam. Attentional demand was assessed with a concurrent voice reaction time (RT) task. Slower RTs, reduced gait speed, and increased number of missteps (>92% of all missteps) were observed during beam-walking. However, walker use reduced attentional demand (faster RTs) and was linked to improved walking performance (increased gait speed, reduced missteps). Data from two healthy older adult cases reveal similar trends. In conclusion, mobility aids can be beneficial by reducing attentional demands and increasing gait stability when balance is challenged. This finding has implications on the potential benefit of mobility aids for persons who rely on walkers to address balance impairments.

Does the Attentional Demands of Walking Differ for Older Men and Women Living Independently in the Community?

Walking has been shown to be an attentionally demanding task. For older adults, gender-specific differences in gait and falling reported in the literature could arise as a result of the attentional demands of walking. However, differences in how older men and women allocate attention to walking have not been investigated. The purpose of this study was to use a dual-task voice reaction time paradigm to examine gender-specific differences in the attentional demands of walking in older adults who are independent in community ambulation. A dual-task paradigm was used to measure voice reaction time (VRT) in older community-dwelling men (n = 29; mean age = 78.40, SD = 6.17 years) and women (n = 33; mean age = 77.01, SD = 6.07 years) under 3 task conditions: sitting in a chair, standing, and walking on a level surface. Between- and within-group differences in dual-task VRT were examined using a 2 (men vs women) by 3 (task condition) repeated-measures analysis of variance. The level of statistical significance was set at 0.05, and a Bonferroni procedure was used for post hoc analyses. Sitting VRT was similar for men (mean = 454.90, SD = 140.05 milliseconds) and women (mean = 454.49, SD = 94.27 milliseconds). While standing, men had a slightly faster VRT (mean = 444.90, SD = 125.31 milliseconds vs mean = 452.09, SD = 92.82 milliseconds). When walking, VRT increased for both groups in comparison to sitting and standing and older men (mean = 509.11, SD = 142.19 milliseconds) responded faster than older women (mean = 537.55, SD = 122.43). However, the main effect of gender (P = .665) and interaction of gender with task (P = .433) were both not statistically significant. A statistically significant main effect for task (P < .001) indicated that walking VRT (mean = 524.25, SD = 131.71 milliseconds) was significantly longer than both sitting (P < .001, mean = 454.68, SD = 116.89 milliseconds) and standing (P < .001, mean = 448.36, SD = 108.37 milliseconds) VRT. The results demonstrate that the attentional demands of walking are not different for older adult men and women who are independent in community mobility. However, support was provided for the idea that walking is an attentionally demanding activity. In comparison with sitting and standing, walking was more attentionally demanding for both men and women. CONCLUSIONS.: A dual-task voice reaction time paradigm revealed that walking is not more attentionally demanding on the basis of gender when comparing community-dwelling older adult men with women.

Effects of ankle and hip muscle fatigue on postural sway and attentional demands during unipedal stance

The effect of muscle fatigue on quiet standing is equivocal, including its duration/recovery and whether it leads to an increase in attentional demands. The purpose of this study was to assess the effects of ankle and hip muscle fatigue on postural sway and simple reaction time during a unipedal task. Two groups of 14 young adults (mean age=22.50±3.23) had to stand on their dominant leg for 30-s trials before and after fatigue of hip or ankle flexors and extensors. Half of the unipedal trials were performed in a dual-task condition where subjects, in addition to standing, had to respond verbally to an auditory stimulus. Sway area, and sway variability and velocity in the AP and ML planes were calculated using center of pressure data obtained from a force platform. Voice reaction time was recorded seated and during the dual-task condition to assess attentional demands. A main effect of fatigue was found for AP sway variability (p=0.027), AP sway velocity (p=0.017) and ML sway velocity (p=0.004). Both groups showed increased sway velocity in both directions and in reaction time during the dual-task condition (p<0.001), but reaction time did not increase with fatigue. A group by fatigue interaction was found significant for ML sway velocity (p=0.043). Results suggest that hip and ankle fatigue affected postural control in the fatigued plane (AP) but only hip fatigue affected postural control in the non-fatigued plane (ML sway velocity). However, fatigue did not lead to an increase in attentional demands and increased AP and ML sway velocity had recovered within 30min.

THE ATTENTIONAL REQUIREMENTS OF STANDING AND WALKING IN PATIENTS COMPLETING ACUTE INPATIENT REHAB AFTER A STROKE

Purpose/Hypothesis: After a stroke (CVA), lesion location may affect the capacity to allocate attention to the acquisition and processing of information necessary to guide motor performance for standing and walking. The purpose of this study was to examine the difference in the capacity to allocate attention to multiple task performance based on hemispheric lesion location in patients who have had a stroke. Number of Subjects: Thirty-two adults, admitted for acute inpatient rehabilitation, were assigned to one of two groups based on lesion location – left CVA (n=14, mean age = 62.9±13.6 yrs), right CVA (n=18, mean age = 62.7±12.8 yrs). At the time of testing, all achieved modified independence for ambulation, had a single, unilateral, first-time lesion and were within 48 hours of discharged from the hospital. Two non-disabled control groups consisting of older (n=18, mean age = 68.3±10.3 yrs) and young (n=18, mean age = 25.9±2.6 yrs) adults also participated. Materials/Methods: A dual-task voice reaction time (VRT) paradigm was used to measure the attentional requirements of completing the two primary functional tasks, standing and walking, by examining changes in performance on a secondary task, the time required to verbally respond to an auditory stimulus by saying the letter “B”. In addition, single and dual-task cadence and gait velocity and overall balance performance was examined. Results: A four (group) × two (task) repeated measures ANOVA revealed significantly slower standing and walking VRT for both CVA groups (p<;.001) when compared to the control groups. Standing and walking VRT did not differ significantly (p=.087) between the post-stroke groups. However, one between task difference appeared for the right CVA group, walking VRT was significantly slower (p<;.001) than standing VRT. There was no statistically significant between group and between task differences in VRT for the control groups. When compared to the control groups, the post-CVA groups walked significantly slower. A comparison of single and dual-task walking performance revealed no statistically significant changes in either cadence or velocity for any of the groups. Conclusions: Among patients who have had a relatively good rehabilitation outcome, the pattern of statistically significant differences in VRT indicates the need for a greater allocation of attentional resources to functional task performance after a stroke. The limitation in the capacity to attend to multiple tasks may be due to one or more lesion specific consequences, such as residual motor defcits, impairments in balance and/or altered capacity for stimulus acquisition and processing. Clinical Relevance: The inability to attend to multiple stimuli is an identifed risk factor for falls in older adults. The participants in this study, while achieving a high level of functional performance for walking, had at least one risk factor, difficulty allocating attention, which places them at increased risk for falling. The literature indicates individuals post-stroke frequently fall soon after being discharged from the hospital.

Changes in Dual-task Voice Reaction Time Among Elders Who Use Assistive Devices

Assistive devices are prescribed for a variety of reasons and have the obvious benefit of enhancing gait performance for some individuals. However, the use of an assistive device may make walking a more complex and cognitively challenging task. The purpose of this study was to use a dual-task voice reaction time (VRT) paradigm to examine the attentional demands of walking with an assistive device in a group of elderly adults. Standing and walking VRTs were measured in a sample of 105 elderly adults who ambulated independently with either a rolling walker (RW; mean age = 87.8 +/- 5.5 yrs), a straight cane (SC; mean age = 84.1 +/- 5.6 yrs), or used no device (ND; mean age = 79. 9 +/- 4.5 yrs). A 3 (group) by 2 (task condition) ANOVA with repeated measures on the last factor was used to examine between and within group differences in VRTs. The main effects of group (p = 0.004) and task (P < 0.001) and the interaction of group with task (P = 0.025) were all statistically significant. There were no statistically significant between group differences in standing VRT. Between group differences appeared during the walking task, VRT for the RW group was significantly longer than for the ND group. When examining within group difference, walking VRT was significantly longer than standing VRT for the SC and RW groups. The results demonstrated that there is an increase in the attentional demands of walking for elderly adults who are experienced assistive device users. The increased attention required to walk with an assistive device may be a factor leading to increased fall risk.

Performance of a psychomotor skill following rest, exercise at the plasma epinephrine threshold and maximal intensity exercise.

The purpose of this study was to examine the effect of exercising at the epinephrine threshold and at Maximum Power Output on the performance of a skill that requires both decision-making and motor performance. Participants (N=12) undertook an incremental test to exhaustion from which their epinephrine threshold and Maximum Power Output were calculated. They were then examined on a soccer skill test following rest and exercise that was previously determined to elicit their epi nephrine threshold and Maximum Power Output. The soccer test examined the participants' speed and accuracy of response. Speed of response was measured by voice reaction time and whole body reaction time. No significant effects of exercise were shown for any of the variables. The need for further research using more complex skill tests and the use of discontinuous exercise protocols, rather than continuous ones, is recommended.

Multiparametric analysis of speech production mechanisms

Describes a new multiparametric approach based on techniques for simultaneous analysis of oromandibular EMG signals and speech in various phonatory reaction tasks, to investigate the speech motor system. Data on latencies of EMG signals (EMG reaction time (RT)) and speech (voice RT) measured during phonatory reaction tasks from both normal subjects of various ages and pathological Parkinsonian subjects are presented. The present methodology has been found to be reproducible, noninvasive and simple, even in pathological cases. Measurements of RT were shown to be useful to analyze in quantitative terms mechanisms involved in speech production and their relationships with certain pathological conditions. In fact, the phonatory RT measurement seems to be helpful to reveal even very subtle or sub-clinical impairments of motor control performance in speech production, which can be greatly affected by aging and by neuromuscular diseases (central or peripheral disorders). >

Voice onset times of stuttering and nonstuttering children: The influence of externally and linguistically imposed time pressure

Differences between stutterers and nonstutterers have been observed less consistently in voice onset time (VOT) than in voice reaction time (VRT) studies. These two experimental paradigms differ in the extent to which time pressure is present during speech. This led to the present study, which was designed to investigate the influence of time pressure on the VOTs of 10 young stutterers and a like number of age- and sex-matched nonstutterers. The children were instructed to read a series of single syllable target words first at a self-selected pace and next as quickly as possible (external time pressure). In addition, artivulatory complexity of the target words was varied systematically (linguistic time pressure). No statistically significant differences were found between the mean VOTs of the stuttering and nonstuttering children. However, the VOTs of the stuttering children were significantly more variable than those of the nonstutterers. None of the group x time pressure interactions reached statistical significance. The present data provide support for the position that VOT and VRT tasks assess different types of speech motor skills.

Voice reaction times with recognition for Commodore computers.

Hardware and software modifications are presented that allow for collection and recognition by a Commodore computer of spoken responses. Responses are timed with millisecond accuracy and automatically analyzed and scored. Accuracy data for this device from several experiments are presented. Potential applications and suggestions for improving recognition accuracy are also discussed.

Nonconscious Perception, Where are You?

In three studies, no evidence of nonconscious perception was found, although general procedures used in previous studies reporting the effect were followed. Presence/absence thresholds (Exps. 1 and 2) or recognition threshold (Exp. 3) were established for each subject. There was no difference in the effects of related and unrelated primes on voice reaction time during a word naming task. These findings raise questions about the robustness of nonconscious priming effects.

Nonconscious perception, where are you?

In three studies, no evidence of nonconscious perception was found, although general procedures used in previous studies reporting the effect were followed. Presence/absence thresholds (Exps. 1 and 2) or recognition threshold (Exp. 3) were established for each subject. There was no difference in the effects of related and unrelated primes on voice reaction time during a word naming task. These findings raise questions about the robustness of nonconscious priming effects.

The effect of foreperiod length on the acoustic voice reaction times of stutterers

A small study was carried out comparing the voice reaction times of stutterers and non- stutterers. A simple reaction time paradigm was used with subjects responding to the offset of a stimulus tone. In this way, the length of the tone and thus the preparatory period were controlled. Short tone durations (≦ 1 sec) were used to discover if stutterers showed greater latencies when given less preparatory time. Stutterers were slower at all tone durations used, but the difference between stutterers and nonstutterers just failed to reach statistical significance. It is recommended that further studies should be undertaken measuring VRT along with other measures, e.g., aerodynamic.

Articulatory-laryngeal interaction in stutterers and normal speakers: Effects of a bite-block on rapid voice initiation

The purpose of this study was to investigate the effects of restricting jaw movement with a bite-block on the voice reaction times (VRT) of adult stutterers and normal speakers. Ten stutterers and ten normal speakers initiated the sound /∧/ as rapidly as possible in response to 1 KHz cues in a nonbite-block and bite-block condition. In the nonbite-block condition all responses were initiated from a mandibular “closed” position. In the bite-block condition the jaw was fixed in a position approximating average jaw displacement for production of /∧/ in a VRT task. Results showed the group mean VRTs for the stutterers were significantly longer than for the normal speakers in both experimental conditions. Group mean VRTs were also significantly faster in the bite-block than the nonbite-block condition for both groups. Investigation of individual subject data, however, revealed that unlike the normal speakers, a subgroup of stutterers exhibited atypically long reaction times and an increase in VRTs with the jaw fixed. The possible role of neurophysiological interactions between articulatory and laryngeal behavior in stuttering is discussed.

Interaction between jaw kinematics and voice onset for stutterers and nonstutterers in a VRT task

The purpose of this study was to investigate the relationship between jaw kinematics and vocal onset of adult stutterers and normal speakers in a voice reaction time task. Ten adult stutterers and ten normal speakers produced /ʌ/ as rapidly as possible in response to twenty-one 1K Hz tones. All responses were initiated with the jaw in a predetermined “closed” position. Results showed that reaction times for both the jaw (JRT) and voice (VRT) were significantly correlated for both groups and that voicing typically began during the final phase of the jaw opening movement. As a group, the stutterers did not differ significantly from the normal speakers for JRT, VRT, or jaw kinematics. Within-group analysis, however, showed that four of the six stutterers exhibited long VRTs and JRTs relative to the distribution of scores for the normal speakers and other stutterers. These subjects also exhibited asynchrony between jaw opening and vocal onset. Results indicate that interaction among upper-articulatory behavior and vocal onset may account, in part, for the long voice reaction times reported for some stutterers.

Subgroups of stuttering children: Speech and voice reaction times, segmental durations, and naming latencies

Speech and voice reaction times, speech segment durations, and object-naming latencies were obtained from a group of nonstuttering children and two subgroups of stuttering children: one subgroup (“stuttering-plus”) consisting of those who needed special education services for problems in addition to stuttering, and the other subgroup (“stuttering-only”) whose only apparent problem was stuttering. The stuttering-plus children had significantly longer speech and voice reaction times and naming latencies than did the stuttering-only and nonstuttering children. The stuttering-only children differed from the nonstuttering children only in voice termination times. The three groups did not differ in speech segment durations or in the variability of such measures. The need for identifying and studying subgroups of stutterers is discussed.

Phonatory initiation, termination, and vocal frequency change reaction times of stutterers

Four types of voice reaction times were investigated for eight adult stutterers and eight control subjects using a vocal shadowing paradigm. These were voice initiation and termination reaction times (VIT and VTT, respectively) and voice frequency-shift intiation and termination reaction times (SIT and STT, respectively). Results indicated that the stutterers were slower in VIT, but were as fast as their control subjects in VTT, SIT, and STT. It was suggested that a laryngeal discoordination problem of stutterers lies primarily in the stage of adduction (turning on the voicing) rather than in the stage of abduction (turning off the voicing) or in finer frequency control at the larynx.

Automatic and expectancy-based priming effects in a digit naming task.

In a voice reaction time task, subjects named target digits that were horizontally flanked by noise digits or by a neutral symbol (#). For the control subjects, the noise digits were uncorrelated with the target digit, whereas for three experimental groups, the value of the noise digit predicted the target digit by an arithmetic rule (target = noise, target = noise + 1, target = noise - 1) on 75% of the trials. Patterns of reaction time facilitation and inhibition relative to the control condition among the four subject groups illustrated differing time courses of involuntary and expectancy-based priming. For prediction rules requiring an arithmetic transformation (expect N = 1 and expect N - 1), responses to predicted targets were slowed by response competition at short stimulus-onset asynchrony (SOAs) but greatly facilitated by expectancy at longer SOAs.