Motor Control and Timing

"Ocular fixation, vestibular dysfunction, and visual motion hypersensitivity." Optometry Volume 80, Issue 9, Pages 502-512 (September 2009)
   Background: A subgroup of individuals with vestibular dysfunction and visual motion hypersensitivity (VMH) become dizzy and imbalanced in response to movement of the visual environment. The purpose of this study was to investigate ocular fixational stability during gaze on a target, with and without visual background movement. Binocular vision functions were also examined as possible contributory factors to the dizziness and imbalance.
   Methods: Twenty-four individuals with VMH, 20 with vestibular disorders without VMH and 20 healthy subjects were tested. Assignment to the experimental group was by symptoms of VMH. Outcome measures included electro-oculogram recordings of horizontal fixation and blink. Four clinical binocular vision functions were also tested. The Dizziness Handicap Inventory was used to assess the level of dizziness.
   Conclusion: Subjects with VMH made significantly more refixational eye movements and had higher levels of dizziness than those in the other 2 diagnostic groups. There were abnormalities of binocular function in both the VMH and vestibular dysfunction groups compared with the control group. Individuals with VMH were unable to maintain stable gaze and inhibit eye movements to background motion. The large number of subjects with diagnosis of fluctuating vestibular function in the VMH group compared with the vestibular dysfunction group may indicate that VMH is a maladaptation of the system.


The Effect of Interactive Metronome Training on Children with ADHD  American Journal of Occupational Therapy (March/April, 2001, Vol 55, No 2)

     In the double blind IM Training 'effect' study, boys with ADHD, who received the Interactive Metronome intervention, were compared with a control group receiving no intervention, and a second control group receiving a placebo computer based intervention. The Interactive Metronome intervention group showed statistically significant improvements over both control groups in areas of attention, motor control, language processing, and reading, and in their ability to regulate aggression.

 New Fundamental Planning & Sequencing Timing Deficiency Patterns  Interdisciplinary Council on Developmental and Learning Disorders Conference (Nov, 1999)
The identification of New Fundamental Planning & Sequencing Timing Deficiency Patterns in children with learning and developmental disorders was announced November 12, 1999 by James Cassily at the Interdisciplinary Council on Developmental & Learning Disorders Third Annual International Scientific Conference held in Washington, D.C..

Interactive Metronome: Effect on Motor Control, Concentration, Control of Aggression, and Learning in Children with Attention Deficit Hyperactivity Disorder   Motor Control II International Conference, Penn State University (Aug, 1999)
    Double blind clinical ADHD Study paper submitted for publication. The IM group also achieved full significance over the placebo control group. The placebo video group's significance findings support the 1998 National Institute of Health's 1998 ADHD Consensus conclusion that studies on interventions must properly control for the positive overall effect that attentive adult interaction is likely to have on the results. Significant differences were found on 11 factors (p values ranging from 0.020 to 0.000) on improving their performance in areas of attention, motor control, language processing, reading, and parental reports of improvements in regulation of aggressive behavior.

Improving Special Education Student Motor Integration by Use of an Interactive Metronome  American Educational Research Association Conference (March, 1997 )  
    The first controlled study of the Interactive Metronome system demonstrated its effectiveness in improving fine and visual motor coordination of special education students. Parent post study observations of improvements in cognitive and behavioral areas led to more comprehensive IM studies to also document the IM 'effect' in these areas.

High/Scope Study (Assessment/ Achievement Correlations)
    585 students aged four to eleven in an Effingham, IL school district were part of a study to assess the reliability and validity of the IM as a measure of motor timing and planning capacity. The results published by the High/Scope Foundation, a prestigious non-profit educational research institution since 1970, showed significant correlations between IM performance and factors of age, motor coordination, attention, academic achievement, and other areas.

J Child Psychol Psychiatry 1998 Sep;39(6):829-40 (Wilson PH, McKenzie BE)
"Information processing deficits associated with developmental coordination disorder: a meta-analysis of research findings."
    A meta-analysis was conducted to identify information processing factors that characterize children with Developmental Coordination Disorder (DCD). A total of 50 studies yielded 374 effect sizes based on 983 DCD and 987 control children. A mild generalized performance deficit was indicated, since motor-impaired children were inferior on almost all measures of information processing. There were, however, several areas where their deficiencies were more pronounced. The greatest deficiency was in visual-spatial processing. This was evident regardless of whether or not the tasks involved a motor component. Most other deficiencies were in the small-to-moderate range and included kinesthetic and cross-modal processing. The findings support the notion that perceptual problems, particularly in the visual modality, are associated with difficulties in motor coordination.

Folia Phoniatr Logop 1998;50(3):107-17 (Gillberg C)
"Hyperactivity, inattention and motor control problems: prevalence, comorbidity and background factors."
    This paper provides a brief review of syndromes associated with activity dysregulation, inattention and motor control problems, usually referred to as attention-deficit/hyperactivity disorder, developmental coordination disorder and deficits in attention, motor control and perception. Several percent of school age children are affected by such problems. Disorders tend to overlap and show significant comorbidities. Familial and brain-damaging factors are involved in the pathogenesis and appear to impinge on specific attentional brain systems. Outcome is variable but restricted if appropriate diagnosis/intervention is not accomplished. Effective interventions are available. Given the high prevalence of these disorders and their relatively poor outcome, such interventions could constitute effective prevention in a general population health perspective.

Dev Med Child Neurol 1998 Dec;40(12):796-804 (Kadesjo B, Gillberg C)
"Attention deficits and clumsiness in Swedish 7-year-old children."
    A population study of 409 seven-year-old children in a middle-sized Swedish town was performed. All children were examined by the same doctor and evaluated by means of parent interview, motor examinations, and teacher reports on behavior in the classroom. Follow-up was carried out 8 months later. The rate of severe problems in the fields of attention deficit-hyperactivity disorder (ADHD), developmental coordination disorder (DCD), and deficits in attention, motor control, and perception (DAMP) (the combination of ADHD and DCD) was 6.1%, with boys being affected more frequently than girls. There was considerable overlap between ADHD and DCD, with about half of each diagnostic group also meeting criteria for the other diagnosis. Attention deficits at diagnosis strongly predicted attention deficits at follow-up. If parents had noted attention deficits in the home setting, then teachers almost always independently agreed that there were similar problems in the classroom. However, the reverse did not always apply. Clumsiness also showed striking stability over time. The diagnosis of DAMP, particularly severe DAMP, had a stronger association with classroom dysfunction and with high Conners scores than did diagnoses of ADHD or DCD. It is concluded that DAMP may be a clinically valid diagnostic construct.

Motor Control 1998 Jan;2(1):61-80  (Elliott D, Ricker KL, Lyons J)
"The control of sequential goal-directed movement: learning to use feedback or central planning?"
    Fifteen participants practiced a two-target sequential aiming movement with either full vision of the movement environment, vision during flight, or vision while in contact with the first target. After 100 acquisition trials, participants performed a retention test in their own condition and then were transferred to each of the other two vision conditions. Both performance and kinematic data indicated that rather than becoming less dependent on visual information with practice, subjects learned to adjust their movement trajectories to use the visual information available in their particular vision condition. Although transfer to a degraded vision condition disrupted performance, when vision was augmented participants quickly adjusted their aiming trajectories to use the added information. The findings suggest that at least part of learning involves the development of rapid and efficient procedures for processing afferent information, including visual response-produced feedback.

Scand J Rehabil Med 1998 Jun;30(2):101-6 (Sigmundsson H, Pedersen AV)
"We can cure your child's clumsiness! A review of intervention methods."
    Intervention procedures for treatment of clumsiness have come in many guises. We have looked at some of the most powerful methods put forward in the past 30 years--Perceptual-motor training (PMT), Sensory Integration Therapy (SIT), and some promising new approaches. Both the PMT and the SIT have been heavily criticized.  It is hard to find support for the idea that the programs improve academic skills or that they have more than a limited effect on perceptual-motor development as claimed.  The more recently introduced kinesthetic training is shown to have an effect on general motor competence but that this may be better explained in terms of the general principles on which this training procedure lies rather than the influence on kinaesthesis per se.  Since other recent studies have also shown a dependence on similar general principles, it might be asked whether it is the teacher rather than the programs that accounts for the differences shown between different intervention programs.

Dev Med Child Neurol 1998 Oct;40(10):672-81 (Smyth MM, Mason UC)
"Use of proprioception in normal and clumsy children."

    This study investigates the relation between performance on simple tasks dependent on proprioception, and performance of complex perceptual-motor skills in clumsy children and age-matched control children. One hundred and forty-six right-handed children aged between 5 and 8 years were tested on non-visual aiming, non-visual posture matching, the Kinaesthetic Sensitivity Test (KST), and the Movement Assessment Battery for Children (ABC). Half of the children had scores below the 15th percentile on the Movement ABC and were classed into the developmental coordination disorder (clumsiness) group. Scores on the proprioceptive tasks were used to predict performance on complex tasks of the subscales of the Movement ABC (manual dexterity, ball skills, and balance). Specific relations were found between the proprioceptive tasks and the subscales of the Movement ABC, but the KST did not predict differences in motor skills, and no relation was found between tasks carried out without vision. Simple non-visual movement tasks do predict performance in more complex skilled tasks but this is affected by many task features rather than simply the reliance on proprioception for information about movement.

Vision Res 1998 Jun;38(12):1817-26 (Langaas T, Mon-Williams M, Wann JP)
"Eye movements, prematurity and developmental co-ordination disorder."
    Horizontal pursuit eye movements were investigated in two separate groups of children: One group exhibited developmental co-ordination disorder (n = 8) whilst another group of children were born prematurely (n = 8). Both studies found a reduced gain in pursuit eye movements when the respective populations were compared with control groups (n = 32). A difference was also found in the ability of some children to temporally synchronize their tracking response to the stimulus, which was indicative of poor predictive control rather than lags in the control system. We suggest that horizontal eye movements may be a sensitive indicator of more general motor deficits during childhood development.

Rev Neurol 1998 Aug;27(156):280-5 (Campos-Castello J)
"Neurological assessment of learning disorders."
    INTRODUCTION: The neurological concept of learning is approached from a cybernetic point of view, taking into account that a child should recognize a fact, learn it semantically and decided whether it is worth storing; the dynamic aspect of memory is the true motor of the ability to learn and all this is modulated by the attention factor.
    DEVELOPMENT: The neurological evaluation of learning disorders is based on clinical examination which includes the so-called minor signs of the noetic functions, specifically language, the praxes, gnosias, perceptive-motor function, laterality and the lexical, graphic and calculation functions together with the modulating element, mentioned above, of the level of attention with or without hyperactivity. These semiological elements are grouped into three major categories of syndromes: motor syndrome, dyslexic-dysgraphic-dyscalculation syndrome and the hyperkinetic syndrome or attention deficit with hyperactivity. We also note the differential diagnosis. We review the neurophysiological biological markers (EEG and brain mapping, cerebral evoked potentials, neurometry) and those based on neuroimaging techniques (cerebral CT, MR, SPECT and PET).
    CONCLUSIONS: The contribution of neurological assessment is considered as part of the functions of a multi-disciplinary team which should deal with the diagnosis and treatment of children with learning disorders.

Dev Med Child Neurol 1998 Jun;40(6):388-95 (Hill EL)
"A dyspraxic deficit in specific language impairment and developmental coordination disorder? Evidence from hand and arm movements."
    The extent to which children with either specific language impairment (SLI) or developmental coordination    disorder (DCD) could be considered dyspraxic was examined using three tasks involving either familiar, or unfamiliar actions. SLI is diagnosed in children who fail to develop language in the normal fashion for no apparent reason, while the DCD diagnosis is applied to a child who experiences problems with movement in the absence of other difficulties. Seventy-two children aged between 5 and 13 years participated, falling into one of four groups: (1) children with specific language impairment (SLI), (2) children with developmental coordination disorder (DCD), (3) age-matched control children, and (4) younger control children. The performance of the clinical groups resembled that of younger normally developing children. Children with SLI, DCD, and the younger controls showed significant difficulty on the task requiring the production of familiar, but not unfamiliar postures. The deficit observed in the SLI group is particularly striking because it was seen both in those with and those without recognized motor difficulties.

Motor Control 1998 Apr;2(2):114-24 (Raynor AJ)
"Fractioned reflex and reaction time in children with developmental coordination disorder."
    The patellar tendon reflex (PTR) and simple visual reaction time (RT) 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. RT, premotor time, and motor time were all significantly (p < .05) increased in children with DCD; the increased RT 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.

Motor Control 1998 Jan;2(1):34-60 (Volman MJ, Geuze RH)
"Stability of rhythmic finger movement in children with a developmental coordination disorder."
    The stability of single and bimanual (i.e., in-phase and antiphase) rhythmic finger movements was studied in 24 children with a developmental coordination disorder (DCD) and 24 matched controls from a dynamic pattern perspective. Stability was assessed by applying perturbations and measuring the time the system needed to return to its initial stability (i.e., the relaxation time). In addition, fluctuations of the patterns were measured. For antiphase coordination patterns, the frequency at which loss of stability occurred was also determined. Children with DCD displayed less stable single and bimanual rhythmic coordination patterns than control children. Further, within the DCD group, 9 children were identified as having particularly poor bimanual coordination stability. Individual differences suggested that variability of individual limb oscillations might have contributed to this poorer interlimb coordination stability. Findings were discussed in relation to a previous study on DCD in which the Wing-Kristofferson timekeeper model was applied.

Percept Mot Skills 1998 Jun;86(3 Pt 1):771-86 (Kioumourtzoglou E, Derri V)
"Cognitive, perceptual, and motor abilities in skilled basketball performance."
    The differences among athletes of differing skill should assist successful identification and selection of the best athletes in a specific sport. For the purpose of this study, a laboratory study was conducted with a group of 13 men on the elite male national team of basketball players, 22 to 23 years of age, and a control group of 15 men of equal age (physical education class) to assess differences in their scores on cognitive skills (memory-retention, memory-grouping analytic ability), perceptual skills (speed of perception, prediction, selective attention, response selection), and motor skills (dynamic balance, whole body coordination, wrist-finger dexterity, rhythmic ability). Analysis showed that elite male basketball players scored higher on hand coordination and lower on dynamic balance given their anthropometric measurements. Elite players were better on memory-retention, selective attention, and on prediction measures than the control group. The above skills are important in basketball performance. Researchers may examine whether other factors contribute more in the development of perceptual and cognitive skills.

Child Care Health Dev 1998 May;24(3):195-205 (Ko ML, McConachie H, Jolleff N)
"Outcome of recommendations for augmentative communication in children."
    Some children with severe motor disorders have unintelligible speech, and may be recommended augmentative communication systems, such as a symbol chart or a voice output aid. The paper reports the outcome after 15-18 months for 35 children of recommendations for augmentative communication. Using structured questionnaires, parents were asked whether equipment was provided as recommended. Their perception of success in children's use of augmentative aids was recorded and related to potentially influential factors. Twenty-five symbol systems, 10 speech output devices and 11 switches were received; 18 symbol systems were used for communication and 10 were used frequently. Seven speech output devices were used for communication but only two were reported to be used frequently. Factors leading to more successful outcomes include early receipt of the aid, perceived adequate local training in the use of the aid, and children aged 6 years or more at initial assessment. The findings also suggest that referring professionals will need to be better informed about the nature and limitations of augmentative communication aids, and that improved local professional input and careful interagency planning and co-ordination are required to achieve optimal outcome.

Dev Med Child Neurol 1998 Feb;40(2):108-14 (Steenbergen B, Hulstijn W, Lemmens IH)
"The timing of prehensile movements in subjects with cerebral palsy."
    In this study, a paradigm is presented for the assessment of manual dexterity in subjects with cerebral palsy (CP) that divides the prehensile action into a 'time-to-contact' phase and a 'time-in-contact' phase. Two experiments were performed that determined the effect of object weight on the timing of both phases for the impaired hand and non-impaired hand of subjects with spastic hemiparesis (N = 14). In the first experiment, subjects had to reach for and lift a tube at their own preferred speed. The results showed that the prehensile deficit of the impaired limb is to a large degree manifested by a longer time spent in contact with the object before it was lifted. The time-in-contact phase was decreased after repeated lifts, suggesting that subjects with CP can control and modify force output in advance based on weight information from preceding lifts. In the second experiment speed of movement execution was stressed to examine whether the observed timing pattern of the first experiment is characteristic of prehensile movements of the paretic arm or represents a movement strategy adapted to the disorder. The results of the second experiment showed that subjects could comply with the instruction by reducing the absolute duration of both phases of the prehensile movement. Furthermore, the anticipation effects were eliminated to a large degree. In both experiments the time-in-contact phase was longer for the impaired limb. These results indicate a pathological constant in the time-in-contact phase for the impaired limb. This assumption is discussed in relation to the application of grip and lift forces during this phase. It is concluded that the paradigm is well suited for use in a practical setting as a simple and broad clinical test to assess the prehensile decrements of subjects with CP.

Exp Brain Res 1998 Dec;123(3):346-50 (Wang J, Stelmach GE)
"Coordination among the body segments during reach-to-grasp action involving the trunk."
    To understand the internal representations used by the nervous system to coordinate multijoint movements, we examined the coordination among the body segments during reach-to-grasp movements which involve grasping by the hand and reaching by the arm and trunk. Subjects were asked to reach and grasp an object using the arm only, the trunk only, and some combinations of both arm and trunk. Results showed that kinematic parameters related to the transport component of the arm and the trunk, such as peak velocity and time to peak velocity, varied across conditions and that the coordination pattern between the arm and trunk was different across conditions. However, parameters related to the grasp component, such as peak aperture, time to peak aperture, and closing distance, were invariant, regardless of whether the hand was delivered to the target by the arm only, the trunk only, or both. We hypothesize that a hierarchy of motor control processes exists, in which the reach and grasp components are governed by independent neuromotor synergies, which in turn are coordinated temporally and spatially by a higher-level synergy.

Harv Rev Psychiatry 1995 May-Jun;3(1):18-35 (Teicher MH)
"Actigraphy and motion analysis: new tools for psychiatry."

    Altered locomotor activity is a cardinal sign of several psychiatric disorders. With advances in technology, activity can now be measured precisely. Contemporary studies quantifying activity in psychiatric patients are reviewed. Studies were located by a Medline search (1965 to present; English language only) cross-referencing motor activity and major psychiatric disorders. The review focused on mood disorders and attention-deficit hyperactivity disorder (ADHD). Activity levels are elevated in mania, agitated depression, and ADHD and attenuated in bipolar depression and seasonal depression. The percentage of low-level daytime activity is directly related to severity of depression, and change in this parameter accurately mirrors recovery. Demanding cognitive tasks elicit fidgeting in children with ADHD, and precise measures of activity and attention may provide a sensitive and specific marker for this disorder. Circadian rhythm analysis enhances the sophistication of activity measures. Affective disorders in children and adolescents are characterized by an attenuated circadian rhythm and an enhanced 12-hour harmonic rhythm (diurnal variation). Circadian analysis may help to distinguish between the activity patterns of mania (dysregulated) and ADHD (intact or enhanced). Persistence of hyperactivity or circadian dysregulation in bipolar patients treated with lithium appears to predict rapid relapse once medication is discontinued. Activity monitoring is a valuable research tool, with the potential to aid clinicians in diagnosis and in prediction of treatment response.

Eur J Appl Physiol 1998 Aug;78(3):219-25 (Wickham JB, Brown JM)
"Muscles within muscles: the neuromotor control of intra-muscular segments."
    The aim of this investigation was to anatomically identify, and then determine the function of, individual segments within the human deltoid muscle. The anatomical structure of the deltoid was determined through dissection and/or observation of the shoulder girdles of 11 male cadavers (aged 65-84 years). These results indicate that the deltoid consists of seven anatomical segments (D1-D7) based upon the distinctive arrangement of each segment's origin and insertion. Radiographic analysis of a cadaveric shoulder joint suggested that only the postero-medial segment D7 has a line of action directed below the shoulder joint's axis of rotation. The functional role of each individual segment was then determined utilising an electromyographic (EMG) technique. Seven miniature (1 mm active plate; 7 mm interelectrode distance) bipolar surface electrodes were positioned over the proximal portion of each segment's muscle belly in 18 male and female subjects (18-30 years). EMG waveforms were then recorded during the production of rapid isometric shoulder abduction and adduction force impulses with the shoulder joint in 40 degrees of abduction in the plane of the scapula. Each subject randomly performed 15 abduction and 15 adduction isometric force impulses following a short familiarisation period. All subjects received visual feed back on the duration and amplitude of each isometric force impulse produced via a visual force-time display which compared subject performance to a criterion force-time curve. Movement time was 400 ms (time-to-peak isometric force) at an intensity level of 50% maximal voluntary contraction. Temporal and intensity analyses of the EMG waveforms, as well as temporal analysis of the isometric force impulses, revealed the neuromotor control strategies utilised by the CNS to control the activity of each muscle segment. The results showed that segmental neuromotor control strategies differ across the breadth of the muscle and that individual segments of the deltoid can be identified as having either "prime mover", "synergist", "stabiliser" or "antagonist" functions; functional classifications normally associated with whole muscle function. Therefore, it was concluded that the CNS can "fine tune" the activity of at least six discrete segments within the human deltoid muscle to efficiently meet the demands of the imposed motor task.