Rosa M. Angulo-Barroso

Effects of Intensity of Treadmill Training on Developmental Outcomes and Stepping in Infants With Down Syndrome : A Randomized Trial

Background and Purpose: Infants with Down syndrome (DS) are consistently late walkers. The purpose of this investigation was to test the effects of individualized, progressively more intense treadmill training on developmental outcomes in infants with DS. Subjects: Thirty infants born with DS were randomly assigned to receive lower-intensity, generalized treadmill training or higher-intensity, individualized training implemented by their parents in their homes. Methods: Research staff members monitored implementation of training, physical growth, and onset of motor milestones of all infants on a monthly basis. Results: Infants in the higher-intensity, individualized training group increased their stepping more dramatically over the course of training. Infants in the higher-intensity training group attained most of the motor milestones at an earlier mean age. Discussion and Conclusion: Treadmill training of infants with DS is an excellent supplement to regularly scheduled physical therapy intervention for the purpose of reducing the delay in the onset of walking.

Exploring effects of different treadmill interventions on walking onset and gait patterns in infants with Down syndrome.

Two cohorts of participants were included to investigate the effects of different treadmill interventions on walking onset and gait patterns in infants with Down syndrome (DS). The first cohort included 30 infants with DS (17 males, 13 females; mean age 10mo [SD 1.9mo]) who were randomly assigned to either a lower‐intensity‐generalized (LG) training group, or a higher‐intensity‐individualized (HI) training group. A control (C) group from another study, who did not receive treadmill training, served as the control (eight males, seven females; mean age 10.4mo [SD 2.2mo]). Mean age at walking onset was 19.2, 21.4, and 23.9 months for the HI, LG, and C groups respectively. At walking onset the HI group was significantly younger than the C group (p=0.011). At the gait follow‐up that was conducted between 1 and 3 months after walking onset, three groups significantly different in overall gait patterns (p=0.037) were examined by six basic gait parameters including average velocity, stride length, step width, stride time, stance time, and dynamic base. Post‐hoc analyses demonstrated that stride length was the gait parameter largely contributing to this overall group difference (p=0.033), and the HI group produced a significantly longer stride length than the C group (p=0.030). In conclusion, the HI treadmill intervention significantly promoted earlier walking onset and elicited more advanced gait patterns (particularly in stride length) in infants with DS.

IRON DEFICIENCY AND INFANT MOTOR DEVELOPMENT

BACKGROUND Iron deficiency (ID) during early development impairs myelination and basal ganglia function in animal models. AIMS To examine the effects of iron deficiency anemia (IDA) and iron deficiency (ID) without anemia on infant motor skills that are likely related to myelination and basal ganglia function. STUDY DESIGN Observational study. SUBJECTS Full-term inner-city African-American 9- to 10-month-old infants who were free of acute or chronic health problems with iron status indicators ranging from IDA to iron sufficiency (n=106). Criteria for final iron status classification were met by 77 of these infants: 28 IDA, 28 non-anemic iron-deficient (NA ID), and 21 iron-sufficient (IS). OUTCOME MEASURES Gross motor developmental milestones, Peabody Developmental Motor Scale, Infant Neurological International Battery (INFANIB), motor quality factor of the Bayley Behavioral Rating Scale, and a sequential/bi-manual coordination toy retrieval task. General linear model analyses tested for linear effects of iron status group and thresholds for effects. RESULTS There were linear effects of iron status on developmental milestones, Peabody gross motor (suggestive trend), INFANIB standing item, motor quality, and toy retrieval. The threshold for effects was ID with or without anemia for developmental milestones, INFANIB standing item, and motor quality and IDA for toy retrieval. CONCLUSIONS Using a comprehensive and sensitive assessment of motor development, this study found poorer motor function in ID infants with and without anemia. Poorer motor function among non-anemic ID infants is particularly concerning, since ID without anemia is not detected by common screening procedures and is more widespread than IDA.

Effects of Various Treadmill Interventions on the Development of Joint Kinematics in Infants With Down Syndrome

Background Infants with Down syndrome (DS) have delayed walking and produce less-coordinated walking patterns. Objective The aim of this study was to investigate whether 2 treadmill interventions would have different influences on the development of joint kinematic patterns in infants with DS. Design Thirty infants with DS were randomly assigned to a lower-intensity, generalized (LG) treadmill training group (LG group) or a higher-intensity, individualized (HI) treadmill training group (HI group) and trained until walking onset. Twenty-six participants (13 in each group) completed a 1-year gait follow-up assessment. Methods During the gait follow-up assessment, reflective markers were placed bilaterally on the participants to measure the kinematic patterns of the hip, knee, and ankle joints. Both the timing and the magnitude of peak extension and flexion at the hip, knee, and ankle joints, as well as peak adduction and abduction at the hip joint, in the 2 groups were compared. Results Both the LG group and the HI group showed significantly advanced development of joint kinematics at the gait follow-up. In the HI group, peak ankle plantar flexion occurred at or before toe-off, and the duration of the forward thigh swing after toe-off increased. Limitations Joint kinematics in the lower extremities were evaluated in this study. It would be interesting to investigate the effect of treadmill interventions on kinematic patterns in the trunk and arm movement. Conclusions The timing of peak ankle plantar flexion (before toe-off) in the HI group implies further benefits from the HI intervention; that is, the HI group may use mechanical energy transfer better at the end of stance and may show decreased hip muscle forces and moments during walking. It was concluded that the HI intervention can accelerate the development of joint kinematic patterns in infants with DS within 1 year after walking onset.

Motor development in 9‐month‐old infants in relation to cultural differences and iron status

Motor development, which allows infants to explore their environment, promoting cognitive, social, and perceptual development, can be influenced by cultural practices and nutritional factors, such as iron deficiency. This study compared fine and gross motor development in 209 9-month-old infants from urban areas of China, Ghana, and USA (African-Americans) and considered effects of iron status. Iron deficiency anemia was most common in the Ghana sample (55%) followed by USA and China samples. Controlling for iron status, Ghanaian infants displayed precocity in gross motor development and most fine-motor reach-and-grasp tasks. US African-Americans performed the poorest in all tasks except bimanual coordination and the large ball. Controlling for cultural site, iron status showed linear trends for gross motor milestones and fine motor skills with small objects. Our findings add to the sparse literature on infant fine motor development across cultures. The results also indicate the need to consider nutritional factors when examining cultural differences in infant development.

Treadmill training in moderate risk preterm infants promotes stepping quality--results of a small randomised controlled trial.

Infants at risk for neuromotor delay (NMD) are associated with premature birth and low birth weight. These infants frequently exhibit tone, posture, and movement abnormalities. Therefore, it is important to identify potential interventions to facilitate early motor development within this population. The purpose of this study was to examine the potential benefits of treadmill (TM) training in infants at risk for NMD. Furthermore, relationships between TM stepping performance and onset of walking have been suggested, and therefore, were also explored. Twenty-eight infants at moderate risk for NMD were randomly assigned to one of two groups: (1) TM training (experimental) (N=15) or (2) control (N=13). Infants in the experimental group were trained for 8 min/day, five days/week from study entry until walking onset. Monthly, 5 min of TM stepping performance were videotaped and analysed for infants in both groups to obtain frequency and quality of TM stepping. Groups were different in terms of TM stepping performance with experimental group displaying better stepping. However, they did not differ in age of walking onset (experimental=15.1 months, control=14.6 months). In both groups, frequency of TM stepping was significantly related to onset of walking. Findings suggest that TM training as implemented impact the quality of TM stepping, but did not significantly improve walking onset. Given the significant relationship between stepping and walking onset, the moderate affection of the population, the relative low intensity and lack of individualisation of the training, we suggest future research should further explore the impact of TM training on gait-related variables and include individualised, more intense, and prolonged training.

High bar swing performance in novice adults: effects of practice and talent.

An individuals a priori talent can affect movement performance during learning. Also, task requirements and motor-perceptual factors are critical to the learning process. This study describes changes in high bar swing performance after a 2-month practice period. Twenty-five novice participants were divided by a priori talent level (spontaneous-talented [ST] and nonspontaneous-talented [NST]) and compared to experienced gymnasts. Additionally, we assessed their perception of their performance level before and after practice. We defined three events independently for hip (H) and shoulder (S) angle joints and for the lag between consecutive events (phases [P]): the smallest angle during downswing (P1H, P1S), the largest angle after P1 (P2H, P2S), and the smaller angle during upswing (P3H, P3S). Movement performance variables were the maximum elevation on the downswing (Pi) and the upswing (Pf), and the total path between both (swing amplitude). Data were collected during pre-and postpractice sessions by two video cameras. At the end of both sessions, participants drew a sketch to represent their perception of their performance level relative to the Pi, Pf, and the hip events. Results showed a similar practice effect in the swing amplitude in both novice groups. However, the ST groups performance and perception variables on the downswing improved more than the NST group due to practice. This study suggests that (a) downswing improvements were easier than in the upswing, possibly due to familiarity of the visual reference in combination with proprioceptive feedback; and (b) being ST may involve a better or faster gain in perception of self-action compared to NST.

Motor Activity and intra-individual variability according to sleep–wake states in preschool-aged children with iron-deficiency anemia in infancy

BACKGROUND A chronic or acute insult may affect the regulatory processes that guide motor and behavioral performance, leading to increased intra-individual variability (IIV). Increased variability is often interpreted as an indication of regulatory dysfunction. Iron plays an important role in the regulatory processes of the nervous system and affects motor activity. To our knowledge, no study has examined the long-lasting patterns and IIV of motor activity following iron-deficiency anemia in human infants. AIMS This study compared 48-h motor activity and variability in preschool-aged children with or without iron-deficiency anemia (IDA) in infancy. METHODS Motor activity was recorded through actigraphs during two week-days in 47 4-year-old Chilean children (23 former IDA and 24 non-anemic in infancy). All were given oral iron as infants. Sleep-wake states were identified by means of automated software. The frequency of movement units per minute was determined for each waking/sleep state during the individual day and night periods; data were examined in blocks of 15 min. Analyses of mean frequency and duration and intra-individual variability were conducted using multivariate mixed models. RESULTS For daytime sleep, former IDA children were more active without a difference in the total duration. They also spent less time awake throughout the individual day period. Motor activity intra-individual variability was higher in former IDA children. CONCLUSIONS The findings suggest that IDA in infancy sets the stage for long lasting dysfunction in the neural processes regulating sleep-wake states and spontaneous motor activity patterns.

Constrained motor-perceptual task in infancy: effects of sensory modality.

The authors examined the relative success of varying sensory stimulation modalities that they presented via a mobile reinforcement procedure for promoting left-knee extensions in 3-month-old infants. They separated 53 infants into 5 groups. Four groups received contingent unimodal auditory, enhanced auditory, or visual reinforcement or contingent bimodal auditory plus visual (aud + vis) reinforcement. One group (controls) received aud + vis noncontingent reinforcement. The group that received aud + vis contingent reinforcement was most successful in learning the motor task and maintained the highest attention levels. The authors observed few differences in learning and attention within the unimodal groups. The present findings confirm the effectiveness of contingent multisensory stimulation for promoting perception-action coupling in infancy.

Effect of Achilles tendon vibration on posture in children

This study investigated the effect of unilateral Achilles tendon vibration on postural response in children and young adults during standing. Thirty healthy subjects participated in this study including ten 6-year-old children (YC group), ten 10-year-old children (OC group), and ten young adults (YA group). Eight-second vibration was elicited in each trial from a small vibrator attached above the right Achilles tendon when participants stood barefoot on a force platform. Three 40-s trials were collected under both eyes-open and eyes-closed conditions. Center of pressure (COP) was calculated to examine postural response during the pre-vibration, vibration and post-vibration phases. Results show that both the YC and OC groups had a greater COP average velocity than the YA group in all three phases. Tendon vibration induced a directionally specific postural response in all three groups such that the onset of vibration induced a posterior and medial COP shift during the vibration phase, and the offset of vibration induced an anterior and lateral COP shift during the post-vibration phase. Timing of the maximal COP shift was comparable among three groups in both anterior-posterior (AP) and medial-lateral (ML) directions. However, only the OC group showed an adult-like magnitude of the maximal COP shift during the post-vibration phase in the AP direction. These results suggest that 6-year-old children may start showing an adult-like directionally specific response and temporal parameter to tendon vibration during standing; however, the development of an adult-like spatial postural response to tendon vibration may take more than 10 years.