This study addressed the question of whether there is a specific reaction time deficit in individuals with Down syndrome. To investigate this question, the manual and vocal reaction times of 18 Down syndrome and 2 control groups were compared. One control group consisted of intellectually handicapped children matched on intellectual ability, the other consisted of younger nonhandicapped children also of similar mental age. The results confirmed that a specific RT deficit does indeed exist and is present for both manual and vocal responses.
Sheila E. Henderson, Sheelagh M. Illingworth and John Allen
Shu-Shih Hsieh, Yu-Kai Chang, Chin-Lung Fang and Tsung-Min Hung
The current study examined the effects of acute resistance exercise (RE) on adult males’ attention control. Eighteen younger males (23.9 ± 2.3 years) and 17 older males (66.4 ± 1.2 years) were recruited. Participants underwent a RE session and a reading session in a counterbalanced order. RE protocol required individuals to perform two sets of 10 repetitions of eight exercises using weights set at 70% of 10-repetition maximum. Attention control was assessed by go/no-go SART with intraindividual variability in reaction times (IIV in RT), in addition to reaction time and accuracy, employed as measures of attention control. Results indicated that IIV in RT was smaller following RE sessions than after reading sessions for both age groups. In addition, RTs were shorter after the exercise session. These findings suggest that RE enhances attention control in adult males and that the size of this effect is not moderated by age.
Annette J. Raynor
The patellar tendon reflex (PTR) and simple visual reaction time (VRT) were fractionated and compared in 40 subjects with developmental coordination disorder (DCD) and normal coordination (NC) in two age groups. Four equal groups of subjects, 6 years DCD (6DCD), 6 years NC (6NC), 9 years DCD (9DCD), and 9 years NC (9NC) were compared using ANOVA for the main effects of coordination and age. PTR and its components of reflex latency and motor time were not significantly affected by the level of coordination; however, a significant coordination by age interaction (p < .05) revealed an increased motor time in the 6DCD group. VRT, premotor time, and motor time were all significantly (p < .05) increased in children with DCD; the increased VRT and premotor time support earlier findings, whereas the increased motor time has not previously been found. These findings suggest that the processing of reflexive and volitional responses by children with DCD differs from that of their NC peers.
Kathye E. Light, Marie A. Reilly, Andrea L. Behrman and Waneen W. Spirduso
The purpose of this study was to examine the effect of practice on simple reaction time (RT), movement time (MT), and response consistency for two arm-reaching tasks of graded complexity in younger and older adults. Forty subjects, 20 younger adults (age range = 20–29 years) and 20 older adults (age range = 60–82 years), were randomly subdivided into practice and control groups. All subjects were pretested on each arm-reaching movement on Day 1. The practice groups practiced each task for 160 trials over 2 consecutive days while the control groups practiced a memory task and answered a health survey. All subjects were posttested on Day 3. The major finding was that practice reduced the simple RTs of older persons to the level of younger persons. MTs for both practice age groups were reduced, but the age differences in MT performance were maintained.
Walter E. Davis, William A. Sparrow and Terry Ward
A fractionation technique was employed to determine the locus of reaction time delay in Down syndrome (DS) and other adult subjects with mental retardation (MH). Twenty-three subjects (8 nondisabled, 8 MH, and 7 DS) responded to a light, sound, and combination light/sound signal. Dependent measures of premotor time, motor time, total reaction time, and movement time were obtained during a 20° elbow extension movement and were analyzed separately. As expected, both MH and DS subjects were slower and more variable in their responses than the subjects without disabilities. In turn, DS subjects were significantly slower but not more variable than the MH subjects. There were no significant differences between the DS and MH subjects on movement times. Evidence for both a specific (premotor) and a generalized (both premotor and motor) locus of delay was found. Some difference in signal effect was also found for the DS subjects.
Alan R. Needle, Thomas W. Kaminski, Jochen Baumeister, Jill S. Higginson, William B. Farquhar and C. Buz Swanik
Rolling sensations at the ankle are common after injury and represent failure in neural regulation of joint stiffness. However, deficits after ankle injury are variable and strategies for optimizing stiffness may differ across patients.
To determine if ankle stiffness and muscle activation differ between patients with varying history of ankle injury.
Fifty-nine individuals were stratified into healthy (CON, n = 20), functionally unstable (UNS, n = 19), and coper (COP, n = 20) groups.
Main Outcome Measures:
A 20° supination perturbation was applied to the ankle as position and torque were synchronized with activity of tibialis anterior, peroneus longus, and soleus. Subjects were tested with muscles relaxed, while maintaining 30% muscle activation, and while directed to react and resist the perturbation.
No group differences existed for joint stiffness (F = 0.07, P = .993); however, the UNS group had higher soleus and less tibialis anterior activation than the CON group during passive trials (P < .05). In addition, greater early tibialis anterior activation generally predicted higher stiffness in the CON group (P ≤ .03), but greater soleus activity improved stiffness in the UNS group (P = .03).
Although previous injury does not affect the ability to stiffen the joint under laboratory conditions, strategies appear to differ. Generally, the COP has decreased muscle activation, whereas the UNS uses greater plantar-flexor activity. The results of this study suggest that clinicians should emphasize correct preparatory muscle activation to improve joint stiffness in injury-rehabilitation efforts.
Christopher P. Tomczyk, George Shaver and Tamerah N. Hunt
baseline had poorer performance on reaction times compared with those without anxiety. 5 • Anxiety at the time of baseline neurocognitive testing may limit an athlete’s ability to perform at maximal capacity, which is necessary when assessing cognitive ability. 5 • Ciucurel 6 examined college
Megan Elizabeth Evelyn Mormile, Jody L. Langdon and Tamerah Nicole Hunt
reaction times. During a baseline examination, females have shown to be 43% more likely to report symptoms associated with concussion, 27 and subsequently have significantly higher total symptom scores. 27 The current study supports these findings, as females reported more than twice the symptoms
Jón Gregersen, Antonis Hatzigeorgiadis, Evangelos Galanis, Nikos Comoutos and Athanasios Papaioannou
experiments on different dimensions of attention: alertness, vigilance, selective attention, focused attention, divided attention, and spatial attention. The results showed that the self-talk groups using attention-alerting or attention-directing instructions had significantly better reaction times compared
Chris Englert and Alex Bertrams
In the current study, we consider that optimal sprint start performance requires the self-control of responses. Therefore, start performance should depend on athletes’ self-control strength. We assumed that momentary depletion of self-control strength (ego depletion) would either speed up or slow down the initiation of a sprint start, where an initiation that was sped up would carry the increased risk of a false start. Applying a mixed between- (depletion vs. nondepletion) and within- (before vs. after manipulation of depletion) subjects design, we tested the start reaction times of 37 sport students. We found that participants’ start reaction times decelerated after finishing a depleting task, whereas it remained constant in the nondepletion condition. These results indicate that sprint start performance can be impaired by unrelated preceding actions that lower momentary self-control strength. We discuss practical implications in terms of optimizing sprint starts and related overall sprint performance.