Development, and construct validity and internal consistency of the Grasp and Reach Assessment of Brisbane (GRAB) for infants with asymmetric brain injury

• Published in: Infant behavior & development 2016-11, Vol.45, p.110-123
• Main Authors: Perez, Micah, Ziviani, Jenny, Guzzetta, Andrea, Ware, Robert S., Tealdi, Gessica, Burzi, Valentina, Boyd, Roslyn N.
• Format: Article
• Language: English
• Subjects: Assessment; Asymmetric brain injury; Construct validity; Infant; Internal consistency; Unilateral cerebral palsy; Upper extremity function
• ISSN: 0163-6383; 1879-0453
• DOI: 10.1016/j.infbeh.2016.10.004

•The Grasp and Reach Assessment of Brisbane (GRAB) is a criterion-referenced measure of reach and grasp.•The GRAB demonstrated moderate to strong construct validity and strong internal consistency.•The GRAB is a consistent measure of reach and grasp within an assessment occasion.•The GRAB quantifies the presence or absence of reach and grasp in infants. Infants with asymmetric brain injury (asymBI) are at high risk of Unilateral Cerebral Palsy (UCP). The Grasp and Reach Assessment of Brisbane (GRAB) was developed to detect asymmetries in unimanual/bimanual upper limb (UL) reach and grasp behaviours in infants with asymBI. This study reports the development of the GRAB and evaluates its construct validity and internal consistency. Prospective study of twenty four infants with asymBI and twenty typically developing (TD) infants at 18 weeks corrected age (C.A.) in a structured play session. Three different coloured toys were presented at the midline in a block design of six 30-s trials of toy presentation, separated by five 30-s trials of no toy presentation. The number and duration of: (i) unimanual contacts; (ii) unimanual grasps; (iii) bimanual midline grasps; and (iv) duration of other unimanual behaviours (e.g. prehensile movements and transport phase) were measured. An Asymmetry Index (AI) was calculated to determine asymmetries between ULs. Possible AI values ranged from 0 to 100%, indicating proportion of toy presentation time that unimanual behaviours were asymmetric between ULs. Internal consistency of both the Time Phase (TP) and Toy Colour Phase (TCP) test items were determined by calculating Cronbach’s alpha coefficients. Each assessment occasion was split into six TPs and two TCPs; whereby one TP comprised one 30-s trial of one toy presentation and one TCP comprised two 30-s trials of the same toy presentation. For TP, seven out of nine unimanual behaviours and two out of three bimanual behaviours demonstrated strong internal consistency (Cronbach’s alpha coefficients 0.72–0.89). No unimanual activity demonstrated the strongest IC (0.89). For TCP, six out of nine unimanual behaviours demonstrated strong IC (0.73–0.82). Number of unimanual contacts and duration of unimanual prehensile movements demonstrated the strongest IC (0.82). Duration of unimanual contribution to hands at midline and duration of bimanual midline behaviour demonstrated the weakest IC for both TP and TCP (0.46–0.50). For unimanual contacts, the asymBI group were more asymmetr