Early development of postural adjustments in standing with and without support

Postural Control in Subjects with Incomplete Partition Inner Ear Malformations: A Comparison of Incomplete Partition Types

INTRODUCTION

Children with inner ear malformation (IEM) are at risk of vestibular loss as well as hearing loss. Incomplete partition (IP) anomalies constitute about 41% of all IEMs. This study aimed to investigate the postural control in subjects with the same type of IP on both sides and to compare their results with cochlear implant (CI) users without IEM and healthy peers.

METHODS

The study group consists of 17 subjects with the same IP types on both sides and using auditory implants on at least one side, with the following 3 groups: 6 IP-I subjects (mean age 12.28 ± 6.25), 6 IP-II subjects (mean age 12.90 ± 3.23), and 5 IP-III subjects (mean age 6.98 ± 3.10). Six unilateral CI users (mean age 11.38 ± 3.57) with normal inner ear structures were included in the CI control group, and 6 healthy peers (10.20 ± 4.79) were included in the healthy control group. The postural control was measured using the Bruininks-Oseretsky Test of Motor Proficiency Second Edition (BOT-2) balance subtest. All devices were turned off during the balance test.

RESULTS

The BOT-2 balance scale scores were observed to be significantly different between the IP-I and healthy control group (medians of balance scores being 3.00 and 16.00, respectively, p < 0.001) and the IP-III and healthy control group (medians of balance scores being 6.60 and 16.00, respectively, p = 0.04). The IP-II group had better balance scores (median = 8.00) than those of the other IP groups, although there were no significant differences between the IP-II and other groups (p > 0.05).

CONCLUSION

This study demonstrated that subjects with the same IP type on both sides and with early implantation may differ in terms of their postural control abilities depending on their IP type. Subjects with IP should be regularly followed up by the vestibular assessment and supported by their postural control ability by vestibular rehabilitation.

Parental Adherence to Home Activities in Early Intervention for Young Children With Delayed Motor Development

OBJECTIVE

The purpose of this study was to investigate the relationship between characteristics of home activities and coaching practices with the adherence of parents of children with motor delays to home activities provided by physical therapists and occupational therapists in early intervention.

METHODS

An online survey study was developed and distributed to physical therapists and occupational therapists across the United States. A survey flier was posted online in parent support groups, physical and occupational therapy groups, newsletters, and organizations supporting parents of children with disabilities.

RESULTS

A total of 720 respondents participated in the survey, and 446 participants from 49 states met the inclusion criteria and were included in the analysis. Parents indicated that physical therapists and occupational therapists applied the 5 coaching practices (joint planning, observation, practice, reflection, and feedback). However, parents (63%) reported more time was needed on coaching. Parents stated that therapists' modeling the activities was the most helpful teaching technique that enhanced their adherence to home activities. Coaching practices, appropriateness of the home activities to daily routines and home environment, provision of home activities enjoyed by the child, and parent self-efficacy were all significantly associated with adherence to home activities.

CONCLUSIONS

Parents' adherence to home activities is affected not only by the type of coaching used by the therapists but also by the characteristics of the home activities provided for young children with delayed motor development.

IMPACT

The results of this study provide additional evidence supporting individualization of home activities to promote parents' continuous provision of learning opportunities to promote their children's development. There was also support of the therapists' use of the 5 coaching practices in early intervention to support the parent's application of home activities when the therapists are not present.

LAY SUMMARY

This study explored the use of home activities from the parents' perspective and provided valuable recommendations to therapists to improve parents' adherence to the recommended home activities in early intervention.

Postural control during reaching while sitting and general motor behaviour when learning to walk

AIM

To study changes in muscular postural strategies and general motor behaviour during the transition to independent walking. Postural control was assessed at its two functional levels: (1) direction specificity, in which dorsal muscles are primarily activated when reaching forward; and (2) fine-tuning of direction specificity.

METHOD

In an explorative longitudinal study, surface electromyograms of the arm, trunk, and neck muscles of 28 typically developing infants were recorded during reaching while sitting. Each infant was assessed in three developmental phases: during pull-to-stand (T0), first independent steps (T1), and 1 month after T1 (T2). Motor behaviour was assessed using the Infant Motor Profile (IMP). The effect on developmental outcome measures (postural parameters and IMP) of the developmental phases (T0, T1, T2) was estimated using linear mixed-effects models.

RESULTS

None of the postural parameters changed significantly over time. However, individual developmental trajectories showed infant-specific postural reorganizational changes. Total IMP score decreased between T0 and T1 (mean IMP score 95% and 91% respectively; p<0.001); between T1 and T2 IMP scores did not change (91% and 93%; p=0.073).

INTERPRETATION

Typically developing infants do not show consistent patterns of postural reorganization but show individual muscular strategies during the transition to independent walking. However, signs of reorganization of general motor behaviour are present.

WHAT THIS PAPER ADDS

Infants show signs of reorganization of motor behaviour when learning to walk. Infants show individual strategies of postural reorganization when learning to walk.

Early human motor development: From variation to the ability to vary and adapt

This review summarizes early human motor development. From early fetal age motor behavior is based on spontaneous neural activity: activity of networks in the brainstem and spinal cord that is modulated by supraspinal activity. The supraspinal activity, first primarily brought about by the cortical subplate, later by the cortical plate, induces movement variation. Initially, movement variation especially serves exploration; its associated afferent information is primarily used to sculpt the developing nervous system, and less to adapt motor behavior. In the next phase, beginning at function-specific ages, movement variation starts to serve adaptation. In sucking and swallowing, this phase emerges shortly before term age. In speech, gross and fine motor development, it emerges from 3 to 4 months post-term onwards, i.e., when developmental focus in the primary sensory and motor cortices has shifted to the permanent cortical circuitries. With increasing age and increasing trial-and-error exploration, the infant improves its ability to use adaptive and efficicient forms of upright gross motor behavior, manual activities and vocalizations belonging to the native language.

Exploring Task-Specific Independent Standing in 3- to 5-Month-Old Infants

Perspectives on developmental milestones suggest that an infant's ability to stand without support occurs at the age of 9-16 months. The two exploratory tasks were part of a baby swimming routine, conducted over a period of 12 weeks (24 sessions), and the aim was to examine whether young infants (mean age 97 days) improved their performance in standing as measured by prolonged time-to-stand. The data suggest that 3- to 5-month-old infants are capable of demonstrating signs of motor learning in task-specific standing. The results appear remarkable when compared to the expected age required for other forms of independent standing. The developmental process of independent standing is discussed in relation to the complex interaction between genetic and environmental factors.

Newly standing infants increase postural stability when performing a supra-postural task

Independent stance is one of the most difficult motor milestones to achieve. Newly standing infants exhibit exaggerated body movements and can only stand for a brief amount of time. Given the difficult nature of bipedal stance, these unstable characteristics are slow to improve. However, we demonstrate that infants can increase their stability when engaged in a standing goal-directed task. Infants' balance was measured while standing and while standing and holding a visually attractive toy. When holding the toy, infants stood for a longer period of time, exhibited less body sway, and more mature postural dynamics. These results demonstrate that even with limited standing experience, infants can stabilize posture to facilitate performance of a concurrent task.

Development of postural adjustments during reaching in typically developing infants from 4 to 18 months

Knowledge on the development of postural adjustments during infancy, in particular on the development of postural muscle coordination, is limited. This study aimed at the evaluation of the development of postural control during reaching in a supported sitting condition. Eleven typically developing infants participated in the study and were assessed at the ages of 4, 6, 10 and 18 months. We elicited reaching movements by presenting small toys at an arm’s length distance, whilst activity of multiple arm, neck and trunk muscles was recorded using surface EMG. A model-based computer algorithm was used to detect the onset of phasic muscle activity. The results indicated that postural muscle activity during reaching whilst sitting supported is highly variable. Direction-specific postural activity was inconsistently present from early age onwards and increased between 10 and 18 months without reaching a 100 % consistency. The dominant pattern of activation at all ages was the ‘complete pattern’, in which all direction-specific muscles were recruited. At 4 months, a slight preference for top-down recruitment existed, which was gradually replaced by a preference for bottom-up recruitment. We conclude that postural control during the ecological task of reaching during supported sitting between 4 and 18 months of age is primarily characterized by variation. Already from 4 months onwards, infants are—within the variation—sometimes able to select muscle recruitment strategies that are optimal to the task at hand.

Anticipatory postural adjustments in children with typical motor development

Anticipatory postural adjustments (APAs) play an important role in the performance of many activities requiring the maintenance of vertical posture. However, little is known about how children utilize APAs during self-induced postural perturbations. A group of children, aged 7-16 years, with typical motor development, performed various arm movements while standing on a force platform. APAs were measured by recording the electromyographic activity of six trunk and leg muscles on both sides of the body and displacement of center of pressure (COP). Anticipatory bursts of activity in the dorsal muscle groups of the trunk and legs and suppression in the ventral muscle groups as well as posterior COP displacement were found during the performance of bilateral shoulder flexion. Conversely, during bilateral shoulder extension, the COP displacement was anterior, and APAs were reversed showing bursts of activity in the ventral muscle groups and suppression in the dorsal muscles. During right and left reciprocal arm movements, COP displacement was minimal and APAs were generated in the dorsal muscle groups on the side of the forward moving arm and in the ventral muscle groups on the side of the arm moving into extension. However this pattern reversed for lower leg muscles, where APAs were generated in the ventral muscles on the side of forward moving arm and in the dorsal muscle on the side of the arm moving into extension. The results of this study indicate that children with typical motor development are able to generate APAs, produce task-specific sequencing of muscle activity and differentiate between perturbations in the sagittal and transverse planes. The results of this study indicate that by at least age 7, children who are typically developing demonstrate the ability to generate patterns of anticipatory muscle activation and suppression, along with center of pressure changes, similar to those reported in healthy adults.