Cognitive and motor aspects of a coincidence-timing task in Cerebral Palsy children.

Cerebral Palsy (CP) is a clinical syndrome involving postural and motor deficits. CP children are less accurate than healthy ones when trying to reach a target. Thus, it is difficult for CP children to perform anticipation-coincidence tasks requiring temporal and/or spatial accuracy to reach the target at the good place in the right time. The purpose of the present experiment was to further investigate CP children's ability to perform anticipation-coincidence tasks, by dissociating the cognitive from the motor aspects of the task. 11 CP children aged 6-14 years, 51 healthy children aged 6-13 years, and 13 healthy adults performed, as accurately as possible, a coincidence-timing in response to a specific sound of a musical sequence. Two experimental conditions were manipulated: In the verbal condition, temporal estimation occurred through a simple verbal response whereas in the motor condition, temporal estimation was performed by reaching a target at a self-paced velocity. In the verbal condition, CP children made similar temporal errors than their healthy counterpart. However, even though all participants underestimated stimulus occurrence, CP children also exhibited greater and more variable temporal errors when they provided a motor response for estimating stimulus occurrence. These data suggested that CP children were able to anticipate stimulus occurrence and to partially take into account their sensory-motor deficits to reach the target at this time occurrence.

The effects of spatial movement components precues on the execution of rapid aiming in children aged 7, 9, and 11.

The aim of the present study was twofold: first, to investigate the effects of spatial precues on the execution of rapid aiming in children aged 7, 9, and 11 and second, to provide a kinematic support to the investigation of the role of precues in aiming tasks performed under temporal constraints. Four precuing conditions were used, where participants received: (a) no precue of any type, (b) advance information on direction, (c) advance information on amplitude, and (d) complete information on the forthcoming movement. Our results showed that precuing the spatial dimensions of movement shortens reaction times, that such shortening is a function of the number of precued parameters, and that spatial precues modify the kinematics of the children's rapid aiming movements. Peak velocity increased with direction and/or amplitude, suggesting that precues play a significant role in motor preparation. Moreover, the accuracy results indicate that direction precuing induces a proactive directional regulation. Finally, direction and amplitude appear to be independently specified in children.

Age-related differences in the preparatory processes of motor programming.

This article investigates the mechanisms underlying the age-related differences in information processing in the production of motor responses, especially the development of feedforward mechanisms. No age-related differences have emerged from developmental studies aiming at analyzing motor programming. Nevertheless, age effects have seldom been studied in function of motor preparation. The aim of the present experiment was (1) to study age differences in motor preparation, and (2) to validate the early maturation of movement parameters specification. Two conditions were used (1) no advanced information on the movement to be made was given to the subject (neutral prime), and (2) advanced information on which direction should be followed was provided to the subject, allowing him to prepare a response based on a prime (primed condition). Four age groups were studied 6, 8, 10 and 22 years. Our results showed mainly an early maturation of the programming processes. More specifically, (1) beyond 6 years of age, children are capable of using the information provided by the prime to prepare their movement in advance, (2) costs and benefits of pre-programming do not vary significantly with age, (3) deprogramming-reprogramming of effector and direction is quite similar across the four age groups.

Monocular and binocular vision in one-hand ball catching: interocular integration.

In 2 experiments, binocular and monocular vision were compared and interocular integration in 1-hand ball catching was examined. Participants (N = 10 in each experiment) were required to catch tennis balls projected over a distance of 15 m. Participants wore liquid-crystal visual occlusion goggles so that the duration and frequency of visual samples provided to their eyes over ball flight could be manipulated. An examination of catching performance indicated that binocular vision contributed to both the spatial and temporal aspects of the catching task. Experienced catchers are able to integrate information from the 2 eyes over intervals as long as 80-100 ms. When provided with only intermittent monocular samples of ball flight, catching performance deteriorated rapidly as the interval between consecutive samples was increased. Results are discussed both in terms of the sources of visual information useful for the interception of objects and the temporal differences for interocular integration between the perception of form and visual-motor control.

Age differences in using precued information to preprogram interception of a ball.

The present experiment examined the development of programming interception of a ball's movement across three groups of children ages 6, 8, and 10 years, who were compared with adults. In an interception task we manipulated the subjects' preparation by using Rosenbaum's 1980 precuing procedure. Two levels of precued information were used concerning the effector specified (right or left arm) and the direction of the arm projection (outside or inside). We focused particularly on RT and response errors. Analysis indicated RT decreased across the age groups and errors decreased mainly in the nonprecued condition. A critical period in improvement might be at age 8 as children use precue information to program their movements as efficiently as adults. The duration of effector programming was similar for children and adults but was more precise for the older subjects. For children as well as for adults, the specification of direction occurs after movement initiation and not before.

Sclerotherapy for hydroceles.

Sclerotherapy with 3% sodium tetradecyl sulfate and 3.5% rolitetracycline on an outpatient basis was applied to 55 hydroceles. The over-all cure rate was 96% with an average followup of 13 months. Of the patients 64% were cured after only 1 sclerosant instillation. A post-sclerotherapy operation was necessary in 4% of the patients. Pain of a significant degree occurred after sclerotherapy in only 29% of the patients. Sclerotherapy appears to be an effective, economical and safe form of outpatient therapy for hydroceles.

Comparative trial of sclerotherapy for hydroceles.

We present a prospective single-blind trial of sclerotherapy for hydroceles with tetradecyl sulphate and rolitetracycline as sclerosants. Twenty-seven hydroceles were treated with tetradecyl sulphate and 28 with rolitetracycline. The median follow-up was 13 months. There were no statistically significant differences between the 2 drugs in respect of cure rate and complications. The overall cure rate for both drugs was 96%. Complications were rare and common to both drugs. Tetradecyl sulphate and rolitetracycline were found to be equally effective as sclerosants.

The effect of semen processing on sperm morphology.

Semen samples were obtained from 28 infertile men referred for AIH. The percentage morphologically normal sperm was assessed on Papanicolaou stained smears before and after semen processing. The percentage of normal sperm increased significantly (p less than 0.005). It would seem that the semen processing procedure increased the number of morphologically normal sperm, which could theoretically improve the results of AIH.