Reporting point and interval estimates of effect-size for planned contrasts: fixed within effect analyses of variance

Handrim Wheelchair Propulsion Technique in Individuals With Spinal Cord Injury With and Without Shoulder Pain: A Cross-sectional Comparison

OBJECTIVE

The aim of this study was to compare handrim wheelchair propulsion technique between individuals with spinal cord injury with and without shoulder pain.

DESIGN

A cross-sectional study including 38 experienced handrim wheelchair users with spinal cord injury was conducted. Participants were divided into the "shoulder pain" ( n = 15) and "no-shoulder pain" ( n = 23) groups using the Local Musculoskeletal Discomfort scale. Kinetic and spatiotemporal aspects of handrim wheelchair propulsion during submaximal exercise on a motor-driven treadmill were analyzed. Data were collected using a measurement wheel instrumented with three-dimensional force sensors.

RESULTS

After correction for confounders (time since injury and body height), linear regression analyses showed that the pain group had a 0.30-sec (95% confidence interval, -0.5 to -0.1) shorter cycle time, 0.22-sec (95% confidence interval, -0.4 to -0.1) shorter recovery time, 15.6 degrees (95% confidence interval, -27.4 to -3.8) smaller contact angle, and 8% (95% confidence interval, -15 to 0) lower variability in work per push compared with the no-pain group. Other parameters did not differ between groups.

CONCLUSIONS

This study indicates that individuals with spinal cord injury who experience shoulder pain propel their handrim wheelchair kinematically differently from individuals with spinal cord injury without shoulder pain. This difference in propulsion technique might be a pain-avoiding mechanism aimed at decreasing shoulder range of motion.

Psychotropic drug use in residents with dementia living in small-scaled special care facilities; a longitudinal study

Objectives: Over the past decade, a trend has been noticed in the Netherlands to replace large-scaled special care units (SCUs) caring for 20-30 residents with dementia by small-scaled SCUs caring for up to 8 residents. Systematic evaluations, however, have yielded a differentiated picture of the effects. As the impact on psychotropic drug use has hardly been addressed thus far, we examined the (potential) impact of psychotropic drug use when moving residents with dementia from large-scaled to small-scaled SCUs.Methods: We conducted a non-randomized, controlled study with a six-month follow-up. Among 145 residents with dementia living a large-scaled SCUs for dementia caring for 20-30 residents per unit, a total of 77 residents were moved to small-scaled SCUs caring for up to 8 residents per unit. Psychotropic drug use, classified according to the Anatomical Therapeutic Chemical Classification (ATC) system was monitored at 2 months before replacement, as well as at 3 and 6 months thereafter. Repeated measures ANOVAs were conducted for the mean Defined Daily Doses (DDDs) of both groups.Results: No significant differences between both groups in psychotropic medication use were found over a period of 8 months.Conclusion: Prescription of psychotropic drugs does not change after a transfer from a large-scaled SCU to a small-scaled SCU of patients with moderate to severe dementia.Current Controlled Trials: ISRCTN11151241.

Quality of life in small-scaled homelike nursing homes: an 8-month controlled trial

Background

Quality of life is a clinical highly relevant outcome for residents with dementia. The question arises whether small scaled homelike facilities are associated with better quality of life than regular larger scale nursing homes do.

Methods

A sample of 145 residents living in a large scale care facility were followed over 8 months. Half of the sample (N = 77) subsequently moved to a small scaled facility. Quality of life aspects were measured with the QUALIDEM and GIP before and after relocation.

Results

We found a significant Group x Time interaction on measures of anxiety meaning that residents who moved to small scale units became less anxious than residents who stayed on the regular care large-scale units. No significant differences were found on other aspects of quality of life.

Conclusions

This study demonstrates that residents who move from a large scale facility to a small scale environment can improve an aspect of quality of life by showing a reduction in anxiety.

Trial registration

Current Controlled Trials ISRCTN11151241. registration date: 21–06-2017. Retrospectively registered.

Rest-activity rhythms in small scale homelike care and traditional care for residents with dementia

Background

An enriched environment for residents with dementia may have a positive effect on the rest-activity rhythm. A small scaled homelike special care unit might be such an enriched environment. The present study shows whether the rest-activity rhythm of residents with moderate to severe dementia responds positively to a transfer from a regular Special Care Unit (SCU) to a small scaled homelike SCU.

Methods

Initially, a group of 145 residents living in a regular SCU participated. Out of this group, 77 residents moved to a small scaled homelike SCU. This group was compared to the group of 68 residents that remained at the regular SCU. Rest-activity rhythm was assessed by means of actigraphy and observation scales before and after relocation.

Results

No significant main effects nor significant interaction effects in intradaily and interdaily activity were found for the data of 38 residents in the small scaled homelike SCU and 20 residents of the regular SCU. The effect sizes, however, ranged from small to large.

Conclusions

Considering the effect sizes, a new study with a larger number of participants is necessary before firm conclusions can be drawn.

Trial registration

Current Controlled Trials ISRCTN11151241. registration date: 21–06-2017. Retrospectively registered.

Potential Mediators in Parenting and Family Intervention: Quality of Mediation Analyses

Parenting and family interventions have repeatedly shown effectiveness in preventing and treating a range of youth outcomes. Accordingly, investigators in this area have conducted a number of studies using statistical mediation to examine some of the potential mechanisms of action by which these interventions work. This review examined from a methodological perspective in what ways and how well the family-based intervention studies tested statistical mediation. A systematic search identified 73 published outcome studies that tested mediation for family-based interventions across a wide range of child and adolescent outcomes (i.e., externalizing, internalizing, and substance-abuse problems; high-risk sexual activity; and academic achievement), for putative mediators pertaining to positive and negative parenting, family functioning, youth beliefs and coping skills, and peer relationships. Taken as a whole, the studies used designs that adequately addressed temporal precedence. The majority of studies used the product of coefficients approach to mediation, which is preferred, and less limiting than the causal steps approach. Statistical significance testing did not always make use of the most recently developed approaches, which would better accommodate small sample sizes and more complex functions. Specific recommendations are offered for future mediation studies in this area with respect to full longitudinal design, mediation approach, significance testing method, documentation and reporting of statistics, testing of multiple mediators, and control for Type I error.

Small scale homelike special care units and traditional special care units: effects on cognition in dementia; a longitudinal controlled intervention study

BACKGROUND

Evidence shows that living in small scale homelike Special Care Units (SCU) has positive effects on behavioural and psychological symptoms of patients with dementia. Effects on cognitive functioning in relation to care facilities, however, are scarcely investigated. The purpose of this study is to gain more insight into the effects of living in small scale homelike Special Care Units, compared to regular SCU's, on the course of cognitive functioning in dementia.

METHODS

A group of 67 patients with dementia who moved from a regular SCU to a small scale homelike SCU and a group of 48 patients with dementia who stayed in a regular SCU participated in the study. Cognitive and behavioural functioning was assessed by means of a neuropsychological test battery and observation scales one month before (baseline), as well as 3 (post) and 6 months (follow-up) after relocation.

RESULTS

Comparing the post and follow-up measurement with the baseline measurement, no significant differences on separate measures of cognitive functioning between both groups were found. Additional analyses, however, on 'domain clusters' revealed that global cognitive functioning of the small scale homelike SCU group showed significantly less cognitive decline three months after the transfer (p < 0.05). Effect sizes (95% CI) show a tendency for better aspects of cognition in favour of the homelike small scaled SCU group, i.e., visual memory, picture recognition, cognitive decline as observed by representatives and the clustered domains episodic memory and global cognitive functioning.

CONCLUSIONS

While there is no significant longitudinal effect on the progression of cognitive decline comparing small scaled homelike SCU's with regular SCU's for patients with dementia, analyses on the domain clusters and effect sizes cautiously suggest differences in favour of the small scaled homelike SCU for different aspects of cognition.

Effect of L-carnitine on exercise performance in patients with mitochondrial myopathy

Exercise intolerance due to impaired oxidative metabolism is a prominent symptom in patients with mitochondrial myopathy (MM), but it is still uncertain whether L-carnitine supplementation is beneficial for patients with MM. The aim of our study was to investigate the effects of L-carnitine on exercise performance in MM. Twelve MM subjects (mean age±SD=35.4±10.8 years) with chronic progressive external ophthalmoplegia (CPEO) were first compared to 10 healthy controls (mean age±SD=29±7.8 years) before they were randomly assigned to receive L-carnitine supplementation (3 g/daily) or placebo in a double-blind crossover design. Clinical status, body composition, respiratory function tests, peripheral muscle strength (isokinetic and isometric torque) and cardiopulmonary exercise tests (incremental to peak exercise and at 70% of maximal), constant work rate (CWR) exercise test, to the limit of tolerance [Tlim]) were assessed after 2 months of L-carnitine/placebo administration. Patients with MM presented with lower mean height, total body weight, fat-free mass, and peripheral muscle strength compared to controls in the pre-test evaluation. After L-carnitine supplementation, the patients with MM significantly improved their Tlim (14±1.9 vs 11±1.4 min) and oxygen consumption (V˙O2) at CWR exercise, both at isotime (1151±115 vs 1049±104 mL/min) and at Tlim (1223±114 vs 1060±108 mL/min). These results indicate that L-carnitine supplementation may improve aerobic capacity and exercise tolerance during high-intensity CWRs in MM patients with CPEO.

Randomized effectiveness trial of a brief course of acupuncture for posttraumatic stress disorder

BACKGROUND

Initial posttraumatic stress disorder (PTSD) care is often delayed and many with PTSD go untreated. Acupuncture appears to be a safe, potentially nonstigmatizing treatment that reduces symptoms of anxiety, depression, and chronic pain, but little is known about its effect on PTSD.

METHODS

Fifty-five service members meeting research diagnostic criteria for PTSD were randomized to usual PTSD care (UPC) plus eight 60-minute sessions of acupuncture conducted twice weekly or to UPC alone. Outcomes were assessed at baseline and 4, 8, and 12 weeks postrandomization. The primary study outcomes were difference in PTSD symptom improvement on the PTSD Checklist (PCL) and the Clinician-administered PTSD Scale (CAPS) from baseline to 12-week follow-up between the 2 treatment groups. Secondary outcomes were depression, pain severity, and mental and physical health functioning. Mixed model regression and t test analyses were applied to the data.

RESULTS

Mean improvement in PTSD severity was significantly greater among those receiving acupuncture than in those receiving UPC (PCLΔ=19.8±13.3 vs. 9.7±12.9, P<0.001; CAPSΔ=35.0±20.26 vs. 10.9±20.8, P<0.0001). Acupuncture was also associated with significantly greater improvements in depression, pain, and physical and mental health functioning. Pre-post effect-sizes for these outcomes were large and robust.

CONCLUSIONS

Acupuncture was effective for reducing PTSD symptoms. Limitations included small sample size and inability to parse specific treatment mechanisms. Larger multisite trials with longer follow-up, comparisons to standard PTSD treatments, and assessments of treatment acceptability are needed. Acupuncture is a novel therapeutic option that may help to improve population reach of PTSD treatment.

The Common Pain of Surrealism and Death

The meaning-maintenance model posits that any violation of expectations leads to an affective experience that motivates compensatory affirmation. We explore whether the neural mechanism that responds to meaning threats can be inhibited by acetaminophen, in the same way that acetaminophen inhibits physical pain or the distress caused by social rejection. In two studies, participants received either acetaminophen or a placebo and were provided with either an unsettling experience or a control experience. In Study 1, participants wrote about either their death or a control topic. In Study 2, participants watched either a surrealist film clip or a control film clip. In both studies, participants in the meaning-threat condition who had taken a placebo showed typical compensatory affirmations by becoming more punitive toward lawbreakers, whereas those who had taken acetaminophen, and those in the control conditions, did not.

An exploratory study of clinician real-time morpho-syntactic judgements with pre-school children

The purpose of this study was to explore the feasibility of employing real-time morpho-syntactic judgements. A system of capturing real-time judgements of children's utterances was implemented using a modified talk-time sampling procedure with 13 monolingual, English-speaking US pre-school children who had standard scores above 85 on a norm-referenced measure of language ability, four of whom had histories of diagnosed language deficits and were receiving language therapy. The remaining participants (n = 9) were typically-developing. The primary research questions were whether the linguistic data from abbreviated talk-time samples were comparable to traditional 100 utterance samples, and whether utterance level judgements made in real-time were in concordance with the linguistic data available in talk-time samples. Results of this investigation revealed positive and significant correlations in linguistic data across both forms of language sampling, as well as statistically significant inverse correlation between real-time judgement of utterance errors and mean length of utterances in morphemes (MLU-m), indicating that clinician decisions about children's utterances were closely associated with morpho-syntactic accuracy. Further analyses revealed that the percentage of conversational utterances with errors was different for children with and without histories of language impairment. Implications for potential clinical application and directions for future research are discussed.

Psychometric functions for shortened administrations of a speech recognition approach using tri-word presentations and phonemic scoring

METHOD

Complete psychometric functions for phoneme and word recognition scores at 8 signal-to-noise ratios from -15 dB to 20 dB were generated for the first 10, 20, and 25, as well as all 50, three-word presentations of the Tri-Word or Computer Assisted Speech Recognition Assessment (CASRA) Test (Gelfand, 1998) based on the results of 12 normal-hearing young adult participants from the original study.

RESULTS

The psychometric functions for both phoneme and word scores were very similar and essentially overlapping for all set sizes. Performance on the shortened tests accounted for 98.8% to 99.5% of the full (50-set) test variance with phoneme scoring, and 95.8% to 99.2% of the full test variance with word scoring. Shortening the tests accounted for little if any of the variance in the slopes of the functions.

CONCLUSIONS

The psychometric functions for abbreviated versions of the Tri-Word speech recognition test using 10, 20, and 25 presentation sets were described and are comparable to those of the original 50-presentation approach for both phoneme and word scoring in healthy, normal-hearing, young adult participants.

Online cognitive-behavioural treatment of bulimic symptoms: a randomized controlled trial

BACKGROUND

Manualized cognitive-behavioural treatment (CBT) is underutilized in the treatment of bulimic symptoms. Internet-delivered treatment may reduce current barriers.

OBJECTIVE

This study aimed to assess the efficacy of a new online CBT of bulimic symptoms.

METHOD

Participants with bulimic symptoms (n = 105) were randomly allocated to online CBT, bibliotherapy or waiting list/delayed treatment condition. Data were gathered at pre-treatment, post-treatment and 1-year follow-up.

OUTCOME MEASURES

The primary outcome measures were the Eating Disorder Examination Questionnaire (EDE-Q) and the frequency of binge eating and purging episodes. The secondary outcome measure was the Body Attitude Test.

RESULTS

Dropout from Internet treatment was 26%. Intention-to-treat ANCOVAs of post-test data revealed that the EDE-Q scores and the frequency of binging and purging reduced more in the online CBT group compared with the bibliotherapy and waiting list groups (pooled between-group effect size: d = 0.9). At 1-year follow-up, improvements in the online CBT group had sustained.

CONCLUSION

This study identifies online CBT as a viable alternative in the treatment of bulimic symptoms.

Standardized web-based cognitive behavioural therapy of mild to moderate depression: a randomized controlled trial with a long-term follow-up

Depression is common but undertreated. Web-based self-help provides a widely accessible treatment alternative for mild to moderate depression. However, the lack of therapist guidance may limit its efficacy. The authors assess the efficacy of therapist-guided web-based cognitive behavioural treatment (web-CBT) of mild to moderate depression. Fifty-four individuals with chronic, moderate depression participated in a randomized wait-list controlled trial, with an 18-month follow-up (immediate treatment: n = 36, wait-list control: n = 18). Primary outcome measures were the Beck Depression Inventory (BDI-IA) and the Depression scale of the Symptom Checklist-90-Revised (SCL-90-R. DEP). Secondary outcome measures were the Depression Anxiety Stress Scales and the Well-Being Questionnaire. Five participants (9%) dropped out. Intention-to-treat analyses of covariance revealed that participants in the treatment condition improved significantly more than those in the wait-list control condition (.011 < p < .015). With regard to the primary measures, between-group effects (d) were 0.7 for the BDI-IA and 1.1 for the SCL-90-R DEP. Posttest SCL-90- R DEP scores indicated recovery of 49% of the participants in the treatment group compared with 6% in the control group (odds ratio = 14.5; p < .004). On average, the effects were stable up to 18 months (n = 39), although medication was a strong predictor of relapse. The results demonstrate the efficacy of web-CBT for mild to moderate depression and the importance of therapist guidance in psychological interventions.

Five-year longitudinal treatment outcomes of the ISTAR Comprehensive Stuttering Program

Replicated evidence of satisfactory 1- and 2-year post-treatment outcomes has been reported for the Comprehensive Stuttering Program (CSP). However, little is known about longer term outcomes of the CSP. Yearly follow-up measures were obtained from 18 participants for 5 consecutive years. At 5-year follow-up, participants were maintaining clinically and statistically significant reductions in stuttering and increases in rates of speech relative to pre-treatment measures. Standardized effect sizes were large. There were no significant differences among the immediate post-treatment and five follow-up measures, indicating that speech gains achieved by the end of the treatment program were stable over the 5-year follow-up period. Insufficient return rates for self-report data for the third to fifth follow-up measurement occasions prohibited analyzing these data. However, non-significant differences among the immediate post-treatment and two follow-up measures indicated that improvements achieved by the end of treatment in speech-related confidence, and perceptions of struggle, avoidance, and expectancy to stutter were stable over the 2-year follow-up period. Significant differences among the speech-related communication attitudes scores indicated that improvements in attitudes made at the end of the treatment program were less stable. Taken together, these results provide further and longer term evidence of the effectiveness of the CSP.

EDUCATIONAL OBJECTIVES

Readers will be able to: (1) describe the main components of the Comprehensive Stuttering Program (2) describe a methodology for determining clinically meaningful maintenance of stuttering reductions, and (3) describe the durability and stability of improvements in speech and self-report measures across time.

Web-based therapist-assisted cognitive behavioral treatment of panic symptoms: a randomized controlled trial with a three-year follow-up

BACKGROUND

Internet-delivered treatment may reduce barriers to care in those unwilling or unable to access traditional forms of treatment.

OBJECTIVE

To assesses the efficacy of web-based therapist-assisted cognitive behavioral treatment (web-CBT) of panic symptoms.

DESIGN

A randomized waiting-list controlled trial with an uncontrolled three-year follow-up.

PARTICIPANTS

A community sample of 58 participants with chronic panic symptoms of varying severity (immediate treatment: n=27, waiting-list control: n=31).

OUTCOME MEASURES

The primary outcome measures were a one-week Panic Diary and the Panic Disorder Severity Scale - Self-Report (PDSS-SR); secondary measures were the Agoraphobic Cognitions Questionnaire (ACQ), the Body Sensations Questionnaire (BSQ), the Mobility Inventory - Alone subscale (MI-AAL), and the Depression Anxiety Stress Scales (DASS-42).

RESULTS

In the RCT, 54 participants (93%) completed posttest measurements. With regard to the primary outcome measures, intention-to-treat ANCOVAs revealed that participants in the treatment condition improved more than the participants in the waiting-list control condition (p<.03), with a pooled between-group effect size of d=.7. After three years (n=47; 81% study compliance), effects were more pronounced.

CONCLUSION

The results demonstrate the efficacy of therapist-assisted web-CBT in the treatment of panic symptoms.

Acute aerobic exercise and information processing: modulation of executive control in a Random Number Generation task

The immediate and short-term aftereffects of a bout of aerobic exercise on young adults' executive functions were assessed. Sixteen participants performed a Random Number Generation (RNG) task, which measured two aspects of executive function, before, during, and after ergometer cycling exercise. In a separate session, participants completed the same sequence of testing while seated on an ergometer without pedaling. Results suggest that aerobic exercise: (1) selectively influences RNG indices related to the ability to alternate ascending and descending runs throughout the entire exercise bout; (2) induces a shift to a less effortful number generation strategy, particularly during the first few minutes of the exercise; and (3) has no significant influence on RNG performance as soon as the exercise terminates. The strategic adjustments observed during the exercise are interpreted in the framework of Hockey's [Hockey, G. R. J. (1997). Compensatory control in the regulation of human performance under stress and high workload: A cognitive-energetical framework. Biological Psychology, 45, 73-93.] compensatory control model and suggest that concurrent effortful processes induced by cycling exercise may draw upon available attention resources and influence executive processing.

Acute aerobic exercise and information processing: energizing motor processes during a choice reaction time task

The immediate and short-term after effects of a bout of aerobic exercise on young adults' information processing were investigated. Seventeen participants performed an auditory two-choice reaction time (RT) task before, during, and after 40 min of ergometer cycling. In a separate session, the same sequence of testing was completed while seated on an ergometer without pedalling. Results indicate that exercise (1) improves the speed of reactions by energizing motor outputs; (2) interacts with the arousing effect of a loud auditory signal suggesting a direct link between arousal and activation; (3) gradually reduces RT and peaks between 15 and 20 min; (4) effects on RT disappear very quickly after exercise cessation; and (5) effects on motor processes cannot be explained by increases in body temperature caused by exercise. Taken together, these results support a selective influence of acute aerobic exercise on motor adjustment stage.

Investigating speech motor practice and learning in people who stutter

In this exploratory study, we investigated whether or not people who stutter (PWS) show motor practice and learning changes similar to those of people who do not stutter (PNS). To this end, five PWS and five PNS repeated a set of non-words at two different rates (normal and fast) across three test sessions (T1, T2 on the same day and T3 on a separate day, at least 1 week apart). The results indicated that PWS and PNS may resemble each other on a number of performance variables (such as movement amplitude and duration), but they differ in terms of practice and learning on variables that relate to movement stability and strength of coordination patterns. These findings are interpreted in support of recent claims about speech motor skill limitations in PWS.

EDUCATIONAL OBJECTIVES

The reader will be able to: (1) define oral articulatory changes associated with motor practice and learning and their measurement; (2) summarize findings from previous studies examining motor practice and learning in PWS; and (3) discuss hypotheses that could account for the present findings that suggest PWS and PNS differ in their speech motor learning abilities.

E-mailed standardized cognitive behavioural treatment of work-related stress: a randomized controlled trial

The aim of this study was to assess the effects of a 7-week standardized cognitive behavioural treatment of work-related stress conducted via e-mail. A total of 342 people applied for treatment in reaction to a newspaper article. Initial screening reduced the sample to a heterogeneous (sub)clinical group of 239 participants. Participants were assigned randomly to a waiting list condition (n = 62), or to immediate treatment (n = 177). A follow-up was conducted 3 years after inception of the treatment. The outcome measures used were the Depression Anxiety Stress Scales (DASS-42) and the Emotional Exhaustion scale of the Maslach Burnout Inventory - General Survey (MBI-GS). Fifty participants (21%) dropped out. Both groups showed statistically significant improvements. Intention-to-treat analysis of covariance (ANCOVAs) revealed that participants in the treatment condition improved significantly more than those in the waiting control condition (0.001<p < or = 0.025). In the treatment group, the effects were large to moderate (0.9 (stress) > or = d > or = 0.5 (anxiety)). The between-group effects ranged from d = 0.6 (stress) to d = 0.1 (anxiety). At follow-up, the effects were more pronounced, but this result requires replication in view of high attrition at follow-up. The results warrant further research on Internet-driven standardized cognitive behavioural therapy for work-related stress. Such research should include the direct comparison of this treatment with face-to-face treatment, and should address the optimal level of therapist contact in Internet-driven treatment.

Temporal envelope changes of compression and speech rate: combined effects on recognition for older adults

PURPOSE

When understanding speech in complex listening situations, older adults with hearing loss face the double challenge of cochlear hearing loss and deficits of the aging auditory system. Wide-dynamic range compression (WDRC) is used in hearing aids as remediation for the loss of audibility associated with hearing loss. WDRC processing has the additional effect of altering the acoustics of the speech signal, particularly the temporal envelope. Older listeners are negatively affected by other types of temporal distortions, but this has not been found for the distortion of WDRC processing for simple signals. The purpose of this research was to determine the circumstances under which older adults might be negatively affected by WDRC processing and what compensatory mechanisms those listeners might be using for the listening conditions when speech recognition performance is not affected.

METHOD

Two groups of adults with mild to moderate hearing loss were tested: (a) young-old (62-74 years, n=11) and (b) old-old (75-88 years, n=14). The groups did not differ in hearing loss, cognition, working memory, or self-reported health status. Participants heard low-predictability sentences compressed at each of 4 compression settings. The effect of compression on the temporal envelope was quantified by the envelope difference index (EDI; T. W. Fortune, B. D. Woodruff, & D. A. Preves, 1994). The sentences were presented at three rates: (a) normal rate, (b) 50% time compressed, and (c) time restored.

RESULTS

There was no difference in performance between age groups, or any interactions involving age. There was a significant interaction between speech rate and EDI value; as the EDI value increased, representing higher amounts of temporal envelope distortion, speech recognition was significantly reduced. At the highest EDI value, this reduction was greater for the time-compressed than the normal rate condition. When time was restored to the time-compressed signals, speech recognition did not improve.

CONCLUSION

Temporal envelope changes were detrimental to recognition of low-context speech for older listeners once a certain threshold of distortion was reached, particularly for rapid rate speech. For this sample tested, the effect was not age related within the age range tested here. The results of the time-restored condition suggested that listeners were using acoustic redundancy to compensate for the negative effects of WDRC distortion in the normal rate condition.