Control of precision grip in children with heavy prenatal alcohol exposure.

Background: Fine motor skill deficits have been reported for children with histories of prenatal alcohol exposure, but little is known whether impaired motor skill extends to the regulation of precision grip control.

Methods: Children with (n = 15) and without (n = 17) histories of heavy prenatal alcohol exposure used their dominant hand to grasp, lift, and hold in space a small-instrumented object with a mass of 19 g. Object mass was also experimentally increased by separately adding two aluminum cubes with mass of 200 and 400 g.

Spiral drawing deficits in children with prenatal alcohol exposure.

Aims: Empirical investigations reveal that, in comparison to their typically developing peers, children with histories of prenatal alcohol exposure experience deficits in writing but not drawing skills, both of which require fine motor control. This study examines drawing skills in this clinical group by assessing simple free-form spiral drawings with indices of spectral features and structural organization.

Methods: Children with (n = 15) and without (n = 24) prenatal alcohol exposure used their dominant and nondominant hands to draw a series of spirals using a wireless pen stylus that either provided concurrent visual feedback in the form of a black ink trace or left no visible ink trace of each drawing.

Gait control in children with attention-deficit/hyperactivity disorder.

The current profile of gait control in children with ADHD is incomplete and predominately based on children walking forward at a self-selected pace. There are no studies of potential gait deficits in this clinical population when walking in different directions in combination with varying rates of stepping that are freely selected and entrained to an external stimulus. The purpose of the current study was to address this lack of information by assessing gait of children aged 7-17 years with (n = 17) and without (n = 26) ADHD.

Computerised Dynamic Posturography in Premanifest and Manifest individuals with Huntington's Disease.

Evidence from small-scale studies indicates that impairments in postural stability are an early and disabling feature of Huntington's disease (HD) and may be a useful clinical endpoint for disease modifying trials. Larger studies are needed to confirm these preliminary findings and the suitability of postural stability outcomes as clinical endpoints. Static and dynamic postural stability were evaluated in 54 premanifest HD, 36 manifest HD and 45 healthy individuals using the Sensory Organization Test (SOT) and Limits of Stability (LOS) test.

A Longitudinal Assessment Of Standing Balance In Healthy Adults.

Unlabelled: Background/Study Context: The study was a longitudinal assessment of age-related changes in standing balance and response strategy usage in healthy adults.

Methods: Balance of 17 individuals with a mean age of 44.5 years was assessed and then reassessed 19.

Children with Heavy Prenatal Alcohol Exposure Exhibit Atypical Gait Characteristics.

Background: Impaired motor function in children with histories of prenatal exposure to alcohol has been previously reported but, to date, no studies using quantitatively based analyses have been performed to assess gait in these children.

Methods: Gait of children with (n = 18) or without (n = 26) prenatal alcohol exposure was assessed using an electronically instrumented walkway. Children completed blocks of trials traversing the walkway with different combinations of walking condition (increased, self-paced, and decreased cadence) and direction (forward and backward).

The Use of Open- and Closed-Loop Control During Goal-Directed Force Responses by Children with Heavy Prenatal Alcohol Exposure.

Background: Many daily functional activities involve goal-directed responses based on open-loop and closed-loop motor control, yet little is known about how children with heavy prenatal alcohol exposure organize and regulate these 2 types of control systems when completing a goal-directed force response.

Methods: Children with (n = 19) or without (n = 23) heavy prenatal alcohol exposure were required to match a target force (25 and 50% of maximum voluntary force) in a specified target time (200, 800, and 2,000 ms). Target force and produced force were visually displayed on a computer monitor.

Postural limits of stability in premanifest and manifest Huntington's disease.

Background: Huntington's disease (HD) is associated with neuronal death in basal ganglia circuits important for postural control. Despite evidence of postural instability associated with HD, postural control at the limits of stability has not been investigated in this disease.

Objective: To use computerized dynamic posturography to measure postural control at the limits of stability during the premanifest and manifest stages of HD.

Children with heavy prenatal alcohol exposure have different frequency domain signal characteristics when producing isometric force.

To extend our current understanding of the teratogenic effects of prenatal alcohol exposure on the control of isometric force, the present study investigated the signal characteristics of power spectral density functions resulting from sustained control of isometric force by children with and without heavy prenatal exposure to alcohol. It was predicted that the functions associated with the force signals would be fundamentally different for the two groups. Twenty-five children aged between 7 and 17 years with heavy prenatal alcohol exposure and 21 non-alcohol exposed control children attempted to duplicate a visually represented target force by pressing on a load cell.

Children with heavy prenatal alcohol exposure experience reduced control of isotonic force.

Background: Heavy prenatal alcohol exposure can result in diverse and extensive damage to the central nervous system, including the cerebellum, basal ganglia, and cerebral cortex. Given that these brain regions are involved in the generation and maintenance of motor force, we predicted that prenatal alcohol exposure would adversely affect this parameter of motor control. We previously reported that children with gestational alcohol exposure experience significant deficits in regulating isometric (i.

Children with heavy prenatal alcohol exposure exhibit deficits when regulating isometric force.

Background: Production of isometric (i.e., constant) force is an essential component of performing everyday functional tasks, yet no studies have investigated how this type of force is regulated in children with confirmed histories of heavy prenatal alcohol exposure.

Co-regulation of movement speed and accuracy by children with heavy prenatal alcohol exposure.

The study investigated how children with heavy prenatal alcohol exposure regulate movement speed and accuracy during goal-directed movements. 16 children ages 7 to 17 years with confirmed histories of heavy in utero alcohol exposure, and 21 nonalcohol-exposed control children completed a series of reciprocal tapping movements between two spatial targets. 5 different targets sets were presented, representing a range of task difficulty between 2 and 6 bits of information.

Postural deficits in Huntington's disease when performing motor skills involved in daily living.

Previous studies of Huntington's disease (HD) have reported motor control deficits for selected fine and gross motor skills. However, no studies have metrically assessed postural control in this clinical group when performing motor skills involved in daily living. Therefore, the purpose of the present study was to evaluate and compare postural control of individuals with confirmed Huntington's disease and non-gene carriers when completing three functional postural tasks.

Impaired postural stability as a marker of premanifest Huntington's disease.

Subtle changes in fine motor control have been observed in individuals who carry the Huntington's disease (HD) mutation but have not yet manifested symptoms, referred to as premanifest HD (preHD). However, few studies have examined gross motor impairments in this population. This study sought to examine the role of sensory involvement in maintaining postural stability during the premanifest and manifest stages of HD using computerized dynamic posturography.

Motor response programming and movement time in children with heavy prenatal alcohol exposure.

The present experiment assessed motor response programming and movement time in children with histories of heavy prenatal alcohol exposure (PEA). Alcohol-exposed children between the ages of 7 and 17 years were classified into two groups: Fetal Alcohol Syndrome (FAS: n=9) and children with PEA (PEA: n=19) but who did not have the defining characteristics of FAS. The FAS and PEA children were compared with non-alcohol-exposed children (NC: n=23) when completing two tasks: a simple reaction time task (RT alone condition) and a reaction plus movement task (RT+Move condition).

Central and peripheral timing variability in children with heavy prenatal alcohol exposure.

Background: The study examined whether prenatal alcohol exposure is associated with increased motor timing variability when the timing response is partitioned into central clock variability, which indexes information processing at the central nervous system (CNS) level and motor delay variability, which reflects timing processes at the level of the peripheral nervous system.

Methods: Eighteen children with histories of prenatal alcohol exposure and 22 control children were assigned to young (7 to 11 years) or older (12 to 17 years) groups. Children tapped a single response key with the index finger in synchrony with a series of externally generated tones (the paced phase).

Stabilization and mobility of the head, neck and trunk in horses during overground locomotion: comparisons with humans and other primates.

Segmental kinematics were investigated in horses during overground locomotion and compared with published reports on humans and other primates to determine the impact of a large neck on rotational mobility (> 20 deg.) and stability (< or = 20 deg.) of the head and trunk.

Motor response selection in children with fetal alcohol spectrum disorders.

Previous work has reported timing delays in motor response selection in children with prenatal exposure to alcohol when the information load involved responding to two stimulus choices. The present study examined whether the delay in response selection extends to conditions in which the information load is increased to four and eight stimulus choices. Twenty children aged between 12 and 17 years with fetal alcohol spectrum disorders (FASD) were compared to 17 non-alcohol-exposed controls (NC) on a reaction time (RT) task involving 1, 2, 4 or 8 visual stimulus choices.

Neuromuscular responses of trained ballet dancers to postural perturbations.

The balance of trained ballet dancers and non-dancer controls was mechanically perturbed in order to evaluate the time of onset of muscle activation and the consistency of muscle activation. Results supported the prediction that ballet dancers have significantly faster long-latency (LL) neuromuscular responses than controls and are significantly more consistent in muscle activation. These findings indicate a superior postural control mechanism in trained dancers and may explain the ability of dancers to maintain static balances over a small base of support.

Sensory organization determinants of postural stability in trained ballet dancers.

Trained ballet dancers and nondancer controls completed six balance tests using computerized dynamic posturography. The tests facilitated assessment of the type of sensory organization used to maintain postural control under conditions ranging from quiet standing to a situation in which visual and/or somatosensory information was systematically removed or made unreliable. Results indicated that ballet dancers and controls have comparable balance ability during eyes open and eyes closed conditions.

Timing accuracy and variability in children with prenatal exposure to alcohol.

Background: Prenatal exposure to alcohol (prenatal alcohol exposure) is associated with gross and fine motor skill dysfunction. The present study examined performance on two types of timing tasks to determine the extent to which prenatal alcohol exposure affects perception, movement planning, and movement execution during tasks that require temporal processing.

Methods: Fourteen children with confirmed heavy prenatal alcohol exposure and 22 control children (aged 5-10 years) completed two timing tasks: a coincident-anticipation timing task that primarily assessed central processing, and a movement-speed timing task that evaluated the motor component of temporal processing.

Fractionated simple and choice reaction time in children with prenatal exposure to alcohol.

Background: The present study investigated central and peripheral processing speed using simple reaction time (SRT) and choice reaction time (CRT) tasks in children who were exposed to alcohol in utero compared with control subjects. Each RT interval was fractionated into premotor and motor components to assess the central processing of stimulus information and peripheral motor unit recruitment, respectively.

Methods: Eleven children with confirmed prenatal alcohol exposure (ALC) and 13 control subjects (NC), aged 5 to 10 years, completed 20 trials of both SRT and CRT tasks.