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The development of trunk control and its relation to reaching in infancy: a longitudinal study.

Rachwani J, Santamaria V, Saavedra SL, Woollacott MH - Front Hum Neurosci (2015)

Bottom Line: Providing external trunk support at different levels to test the effects of controlling the upper and lower regions of the trunk on reaching provides insight into the mechanisms by which trunk control impacts reaching in infants.Differences between levels of support were not observed once infants acquired independent sitting.These results suggest that trunk control is acquired in a segmental sequence across the development of upright sitting, and it is tightly correlated with reaching performance.

View Article: PubMed Central - PubMed

Affiliation: Human Physiology and Institute of Neuroscience, University of Oregon Eugene, OR, USA.

ABSTRACT
The development of reaching is crucially dependent on the progressive control of the trunk, yet their interrelation has not been addressed in detail. Previous studies on seated reaching evaluated infants during fully supported or unsupported conditions; however, trunk control is progressively developed, starting from the cervical/thoracic followed by the lumbar/pelvic regions for the acquisition of independent sitting. Providing external trunk support at different levels to test the effects of controlling the upper and lower regions of the trunk on reaching provides insight into the mechanisms by which trunk control impacts reaching in infants. Ten healthy infants were recruited at 2.5 months of age and tested longitudinally, until 8 months. During the reaching test, infants were placed in an upright seated position and an adjustable support device provided trunk fixation at pelvic and thoracic levels. Kinematic and electromyographic data were collected. Results showed that prior to independent sitting, postural instability was higher when infants were provided with pelvic compared to thoracic support. Associated reaches were more circuitous, less smooth and less efficient. In response to the instability, there was increased postural muscle activity and arm muscle co-activation. Differences between levels of support were not observed once infants acquired independent sitting. These results suggest that trunk control is acquired in a segmental sequence across the development of upright sitting, and it is tightly correlated with reaching performance.

No MeSH data available.


Related in: MedlinePlus

Graphs above showing examples of the 3D trajectory of a single reach from onset (circular shape) to offset (diamond shape), of one infant with thoracic and pelvic support during (A) 3 months prior to sitting onset and (B) 1 month after sitting onset. Photographic images show infant reaching toward the toy with thoracic and pelvic support at 3 months prior to sitting onset. Arrows indicate location of kinematic sensors.
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Figure 3: Graphs above showing examples of the 3D trajectory of a single reach from onset (circular shape) to offset (diamond shape), of one infant with thoracic and pelvic support during (A) 3 months prior to sitting onset and (B) 1 month after sitting onset. Photographic images show infant reaching toward the toy with thoracic and pelvic support at 3 months prior to sitting onset. Arrows indicate location of kinematic sensors.

Mentions: Major differences in reach outcomes between levels of external support were observed during the months prior to sitting onset. The graphs from Figure 3 are examples of a reach at the thoracic and pelvic level of support of an infant 3 months before and 1 month after sitting onset. A photographic image is shown of the infant reaching with each level of support at 3 months before sitting onset. The 3-dimensional visual representation of the arm trajectory shows how the infant displayed a more circuitous reach and was more unstable with pelvic support compared to thoracic support prior to the development of independent sitting ability, and this difference was not observed once this milestone was acquired.


The development of trunk control and its relation to reaching in infancy: a longitudinal study.

Rachwani J, Santamaria V, Saavedra SL, Woollacott MH - Front Hum Neurosci (2015)

Graphs above showing examples of the 3D trajectory of a single reach from onset (circular shape) to offset (diamond shape), of one infant with thoracic and pelvic support during (A) 3 months prior to sitting onset and (B) 1 month after sitting onset. Photographic images show infant reaching toward the toy with thoracic and pelvic support at 3 months prior to sitting onset. Arrows indicate location of kinematic sensors.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4338766&req=5

Figure 3: Graphs above showing examples of the 3D trajectory of a single reach from onset (circular shape) to offset (diamond shape), of one infant with thoracic and pelvic support during (A) 3 months prior to sitting onset and (B) 1 month after sitting onset. Photographic images show infant reaching toward the toy with thoracic and pelvic support at 3 months prior to sitting onset. Arrows indicate location of kinematic sensors.
Mentions: Major differences in reach outcomes between levels of external support were observed during the months prior to sitting onset. The graphs from Figure 3 are examples of a reach at the thoracic and pelvic level of support of an infant 3 months before and 1 month after sitting onset. A photographic image is shown of the infant reaching with each level of support at 3 months before sitting onset. The 3-dimensional visual representation of the arm trajectory shows how the infant displayed a more circuitous reach and was more unstable with pelvic support compared to thoracic support prior to the development of independent sitting ability, and this difference was not observed once this milestone was acquired.

Bottom Line: Providing external trunk support at different levels to test the effects of controlling the upper and lower regions of the trunk on reaching provides insight into the mechanisms by which trunk control impacts reaching in infants.Differences between levels of support were not observed once infants acquired independent sitting.These results suggest that trunk control is acquired in a segmental sequence across the development of upright sitting, and it is tightly correlated with reaching performance.

View Article: PubMed Central - PubMed

Affiliation: Human Physiology and Institute of Neuroscience, University of Oregon Eugene, OR, USA.

ABSTRACT
The development of reaching is crucially dependent on the progressive control of the trunk, yet their interrelation has not been addressed in detail. Previous studies on seated reaching evaluated infants during fully supported or unsupported conditions; however, trunk control is progressively developed, starting from the cervical/thoracic followed by the lumbar/pelvic regions for the acquisition of independent sitting. Providing external trunk support at different levels to test the effects of controlling the upper and lower regions of the trunk on reaching provides insight into the mechanisms by which trunk control impacts reaching in infants. Ten healthy infants were recruited at 2.5 months of age and tested longitudinally, until 8 months. During the reaching test, infants were placed in an upright seated position and an adjustable support device provided trunk fixation at pelvic and thoracic levels. Kinematic and electromyographic data were collected. Results showed that prior to independent sitting, postural instability was higher when infants were provided with pelvic compared to thoracic support. Associated reaches were more circuitous, less smooth and less efficient. In response to the instability, there was increased postural muscle activity and arm muscle co-activation. Differences between levels of support were not observed once infants acquired independent sitting. These results suggest that trunk control is acquired in a segmental sequence across the development of upright sitting, and it is tightly correlated with reaching performance.

No MeSH data available.


Related in: MedlinePlus