Infant Reaching in the First Year of Life: A Scoping Review of Typical Development and Examples of Atypical Development

Abstract

Aims

Our objective was to identify the most common variables used for infant reaching assessment, describe values of these variables across the first year of life, and identify methodological considerations and knowledge gaps for future research.

Methods

Studies were included if they met the following criteria: (1) assessed infant reaching in any position, (2) included a sample of infants with typical development: healthy, full-term, with no known impairments, (3) infants were under one year old at the first data collection, and (4) counted successful reaches resulting in object contact.

Results

We identified 6 commonly assessed kinematic reaching variables: frequency, duration, movement units, peak velocity, average velocity, and straightness index. Methodological inconsistencies limit our ability to interpret values of these variables across studies.

Conclusions

Eliminating inconsistencies in study design and data analysis methods is the next step to defining a normative reference standard for reaching development. Establishing a normative reference standard for reaching in the first year of life will be important for assessment of typical and atypical reaching development.

Keywords:

• Infant
• kinematics
• motor assessment
• motor development
• reaching

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Judy Zhou

Judy Zhou, PT, DPT, is a PhD Student in Biokinesiology and a teaching assistant in the Doctor of Physical Therapy program at the University of Southern California where she teaches Integrated Patient Management and Analytical Anatomy. Her research interests are related to reaching and motor planning in infants at high risk for autism spectrum disorder with emphasis on identifying differences for early intervention. She would like to use video coding and kinematic analysis to develop different movement intervention targets for infants with or at high risk for various developmental disabilities.

Beth A. Smith

Beth A. Smith, PT, DPT, PhD, is Associate Professor of Pediatrics. She directs the Infant Neuromotor Control Laboratory at Children’s Hospital Los Angeles, which studies the development of neural control of movement during infancy and evaluates interventions for neural and functional development in infants with or at risk for developmental disabilities. Her current work uses wearable sensors, electroencephalography, eye-gaze tracking, and video coding to study infant movement behavior and learning.