Neonatal Behavioral Assessment Scale (NBAS)

Original Editor - Lauren Heydenrych

Top Contributors - Lauren Heydenrych  

Introduction[edit | edit source]

The first 3 years of life in a child's life are described as a "key period of physical, physiological, cognitive and social development" by Barlow et al (2018)[1] Despite this, much of the predominant medical views of the early 20th centaury asserted that neonates and even infants a few months old were passive receptors of sensory stimuli and governed mainly by primitive reflexes. Assessment tools focused on primitive reflexes, postural reactions and general physical competence.[2]

Following advances in the different spheres of medicine, including psychology and psychiatry understanding grew that an infant, even hours after birth could orientate and react appropriately to stimuli[2].

The Neonatal Behavioral Assessment Scale (NBAS) is a neurobehavioral assessment. It is a tool used to describe an infant's interaction with their extrauterine environment. Furthermore, it highlights the emerging relationship between caregiver and infant, ultimately presenting a holistic picture of clinical conditions of both term and preterm infants. [3][4]

Constructed by Brazelton in 1973, the NBAS underwent revision in 1984 and 1995. In 2000 the Newborn Behavioural Observation System (NBO) was constructed as a new flexible shortform version of the NBAS.[3]

Objective[edit | edit source]

  1. The NBAS is used as an assessment tool to assess:
    • An infants behavioural repertoire.[5]
    • The competencies in both healthy and at-risk infants.[4]

The NBAS does not simply detect abnormalities, but highlights an infants strengths and individualities.[5]

2. It is also used as an identifier of prenatal and neonatal factors which influence development and behaviour. [4]

3. The NBAS has also been increasingly used as an intervention tool, to improve the sensitivity and quality of the caregiver-infant relationship. This includes improving the bonding relationship of caregivers and infants born blind, infants with Down Syndrome and infants born into low socioeconomic status[4]

With a series of examinations, the NBAS allows those examining to observe the integration of discrete behaviours of the infant into coherent patterns of behaviour and development.[5]

Intended Population[edit | edit source]

The intended age population for the NBAS is from birth up to 2 weeks after birth.[5]

It can be used in term and preterm infants.

While infants need to be medically stable, those with known and suspected disabilities/ difficulties can also have the NBAS administered.

Administration[edit | edit source]

Environment/ Setting[edit | edit source]

The NBAS can be administered in a variety of settings, including in the clinic, in a ward or even in the home. The space chosen should be intimate enough to limit interruption form the 'outside world' and allow caregivers time and space to interact with the infant.

Frequency of administration[edit | edit source]

Frequency of administration is dependent upon the goals for performing the NBAS.

With a single administration, a window into the infants current behavioural competencies and repertoires can be gained. However, a series of administrations can give a more holistic picture of the infant.[6]

Content[edit | edit source]

The NBAS consists of:

  • 28 behavioural items - scored on a 9 point scale.
  • 20 reflex items - scored on a 4 point scale.

Note: The assessment of reflexes is not to provide a neurological diagnosis, but to identify gross neurological abnormalities.

These items are clustered into 4 developmental domains:

  1. Autonomic regulation
  2. Motor development
  3. State regulation
  4. Social engagement

Scoring[edit | edit source]

A single score is not calculated, rather the infants capabilities across different developmental domains is recorded together with their integration of behaviour in response to the environment.

Links[edit | edit source]

The Newborn Behavior International site.

References[edit | edit source]

  1. Barlow J, Herath NI, Torrance CB, Bennett C, Wei Y. The Neonatal Behavioral Assessment Scale (NBAS) and Newborn Behavioral Observations (NBO) system for supporting caregivers and improving outcomes in caregivers and their infants. Cochrane Database of Systematic Reviews. 2018(3).
  2. 2.0 2.1 The Neonatal Behavioral Assessment Scale (NBAS) - Background and Conceptual Basis. Psychology, Medicine. 2011.
  3. 3.0 3.1 Canals J, Fernández-Ballart J, Esparó G. Evolution of neonatal behavior assessment scale scores in the first month of life. Infant Behavior and Development. 2003 Apr 1;26(2):227-37.
  4. 4.0 4.1 4.2 4.3 Malak R, Fechner B, Sikorska D, Rosołek M, Mojs E, Samborski W, Baum E. Application of the neonatal behavioral assessment scale to evaluate the neurobehavior of preterm neonates. Brain sciences. 2021 Sep 28;11(10):1285.[1]
  5. 5.0 5.1 5.2 5.3 Brazelton Institute. Neonatal Behavioral Assessment Scale (NBAS). Available from: (accessed 27 November 2023)
  6. Bartram SC, Barlow J, Wolke D. The Neonatal Behavioral Assessment Scale (NBAS) and Newborn Behavioral Observations system (NBO) for supporting caregivers and improving outcomes in caregivers and their infants. Cochrane Database of Systematic Reviews. 2015 Jun 21(6).
  7. Brazelton Centre UK. What is the NBAS?. Available from: [last accessed 05/12/2023]
  8. FWIChannel. Brazelton Presentation. Available from: [last accessed 05/12/2023]