IMP in professional practice: reliability and responsiveness

Paediatric physical therapists (PTs) use for the evaluation of infant motor
development virtually always the Alberta Infant Motor Scale (AIMS) The AIMS is
reliable, but has a ceiling effect for its oldest age-range (16-18 months).
Moreover, its capacities to evaluate motor development are moderate only. For
the latter two explanations may be offered. First, the AIMS only evaluates
gross motor development and not fine motor skills. Second, the AIMS measures
motor development only in terms of motor milestones.
Recently the IMP was developed; it measures gross and fine motor development.
In addition, it does not only describe motor development in terms of motor
milestones (performance), but also in terms of variation (size of the motor
repertoire), variability (ability to select proper strategies from the
repertoire), symmetry, and movement fluency. These motor domains tap on the
domains in which PTs may offer specific guidance for the infants.
IMPs reliability and validity in the research setting are sufficient to very
good. Yet, it is unclear whether the IMP has similar psychometric properties
when applied in daily practise of paediatric physical therapy (PPT).

To assess reliability and responsiveness of the IMP in PPT practise. IMP*s
responsiveness will be compared to that of the AIMS. .

For the assessment of IMP's responsiveness:
Assessment of 25 infants, aged 3-12 months corrected age (CA) at study entry,
who receive PPT for developmental dysfunction. The infants will be assessed
three times with the IMP (the IMP assessment is video-recorded): at inclusion
(T0), after 3 months (T1) and 6 months (T2) after inclusion. On the basis of
the video recording not only the IMP-scores will be determined but also the
AIMS scores. At T0 Parents fill out a concise and standardized questionnaire on
demographic and pre-, peri- and neonatal characteristics. The PTs supply
information on planned treatment goals and actions at T0 and T1. Parents and
paediatric PTs score at T1 and T2 on a visual analogue scale (VAS) the infant's
develomental progress.(1 item, scale 0-10 points). In this way it is possible
to explore: a) whether IMP-scores change during PPT; b) whether IMP-scores are
more sensitive to change than AIMS-scores; c) whether IMP-scores are associated
with physiotherapeutic goals and actions, and with parental and PTs perceptions
of the infant's developmental progress.
For the assessment of IMP's reliability:
- IMP assessments at T0 of the 25 infants of the responsiveness study
- IMP assessments of 16 additional infants aged 11-18 months CA, who receive
PPT because of developmental dysfunction.
The 41 IMP-video's will be assessed by 3 raters: a) the PT in charge of the
infant's treatment; b) another PT participating in this study; c) an
investigator at the Institute of Developmental Neurology of the UMCG.
Reliability will be determined by means of a two-way ANOVA model defining
subjects and raters as random effect.

The burden of the study is low. It consists of 3 IMP-assessments, involving a
play session of about 15 minutes. Infants in general enjoy the IMP-assessment.
In addition parents will fill out a small questionnaire on demographic and
pre-, peri- and neonatal characteristics of the infant (10 minutes) and will
rate 2x a VAS score on the infant's developmental progress.
Participation in the study is not associated with risk.
The benefits are: a) on individual level: parents receive detailed information
on the motor development of their infant; b) on health care level: the study
may reveal that the IMP is an adequate tool to monitor motor development in
infants receiving PPT.