Suzann K. Campbell

Validity of the Test of Infant Motor Performance for prediction of 6‐, 9‐ and 12‐month scores on the Alberta Infant Motor Scale

The Test of Infant Motor Performance (TIMP) is a test of functional movement in infants from 32 weeks’post‐conceptional age to 4 months postterm. The purpose of this study was to assess in 96 infants (44 females, 52 males) with varying risk, the relation between measures on the TIMP at 7, 30,60, and 90 days after term age and percentile ranks (PR) on the Alberta Infant Motor Scale (AIMS). Correlation between scores on the TIMP and the AIMS was highest for TIMP tests at 90 days and AIMS testing at 6 months (r=0.67,p=0.0001), but all comparisons were statistically significant except those between the TIMP at 7 days and AIMS PR at 9 months. In a multiple regression analysis combining a perinatal risk score and 7‐day TIMP measures to predict 12‐month AIMS PR, risk, but not TIMP, predicted outcome (21% of variance explained). At older ages TIMP measures made increasing contributions to prediction of 12‐month AIMS PR (30% of variance explained by 90‐day TIMP). The best TIMP score to maximize specificity and correctly identify 84% of the infants above versus below the 10th PR at 6 months was a cut‐off point of 1 SD below the mean. The same cut‐off point correctly identified 88% of the infants at 12 months. A cut‐off of‐0.5 SD, however, maximized sensitivity at 92%. A negative test result, i.e. score above ‐0.5 SD at 3 months, carried only a 2% probability of a poor 12‐month outcome. We conclude that TIMP scores significantly predict AIMS PR 6 to 12 months later, but the TIMP at 3 months of age has the greatest degree of validity for predicting motor performance on the AIMS at 12 months and can be used clinically to identify infants likely to benefit from intervention.

Evaluating research in developmental disabilities: a conceptual framework for reviewing treatment outcomes

The study of developmental disabilities, not being confined to one medical field, poses a challenge in evaluating outcomes research. It is a multidisciplinary area of study which encompasses health-care, rehabilitation, psychosocial, educational, and biotechnology specialties and involves biological, social, and behavioral effects of intervention. Consequently, there is a lack of consistency in what has been studied, how the outcomes have been measured, and where these results have been recorded. Naturally, these disparate outcomes data need to be consolidated in such a way that comparison of treatments can be made, within and across professional disciplines. In an attempt to facilitate this, the American Academy for Cerebral Palsy and Developmental Medicine (AACPDM) is committed to providing critical and useful appraisal of the scientific literature to help clinicians keep abreast in their own as well as other relevant disciplines1. The Academy has explored several classification systems to consolidate and interpret data, and has established a two-part conceptual framework (1) to aggregate treatment outcomes and construct evidence tables based on a model of disablement which classifies treatment outcomes by the dimension in which they have an effect; and (2) to determine the degree of confidence that can be placed in the scientific evidence available in support of an intervention.

Somatotopic organization of the external cuneate nucleus in albino rats

Abstract The pattern of representation of muscle receptive fields was delineated in the external cuneate nucleus (EC) of anesthetized, cerebellectomized albino rats. This nucleus was explored systematically using ball-tipped tungsten microelectrodes and closely-spaced electrode punctures. Single neurons were recorded from and the peripheral source and modality of their activating receptive fields were identified using natural stimulation of exposed muscles of the rats forequarter. Each muscle was stimulated by pulling the tendon, pressure to its belly with fine probes and/or by stretch induced by joint rotation. Of 585 single units recorded from 411 punctures in 31 animals, 243 were localized to EC and were activated by stretch at low threshold or punctate pressure of muscles of the ipsilateral forequarter. All cells definitely localized within EC by histological verification were activated only from receptive fields located in muscle. The musculotopic pattern of organization of peripheral projections within the three-dimensional confines of EC was rather detailed, with neck muscles represented in its rostrolateral pole, arm and shoulder muscles more caudomedially, and forearm and hand muscles progressively more caudally. There was no overlap of representations from muscles located in different anatomical segments. EC units for which receptive field identification was certain were always activated from a single muscle. However, those units whose fields could not be identified precisely may have received convergent activation (or inhibition) from different muscles which our procedures did not allow us to detect. No units in EC were activated from cutaneous receptive fields, nor did we find convergence of activation from cutaneous and muscle receptive fields. EC cells were never activated from receptive fields in the hindlimb or contralateral forelimb.

Evidence for the need to renorm the Bayley Scales of Infant Development based on the performance of a population-based sample of 12-month-old infants.

Assessment on the Bayley Scales of Infant Development of 305 twelve-month-old infants born at full term (>2,500 grams) in rural North Carolina resulted in mean Mental Developmental Indexes (MDIs) of 114 and 109 for whites and nonwhites, respectively, and a mean Psychomotor Developmental Index (PDI) of 110 for each group. Because the sample was systematically drawn from the entire population of an eight-county region, such high scores raised the suspicion that the 1969 Bayley norms are outdated. Exploration of alternative hypotheses suggested that home testing might have positively affected sample scores, but support for the hypothesis that the Bayley norms for 12-month-olds are outdated was derived from published means for other samples of infants born in the 1970s and from recent age placement revisions of items on the Gesell Developmental Examination. A renorming of the Bayley Scales is recommended.

Efficacy of a Neuro-Developmental Treatment Program to Improve Motor Control in Infants Born Prematurely

The purpose of this study was to evaluate the efficacy of a Neuro-Developmental Treatment protocol designed to improve motor control in infants born prematurely and at high risk for developmental disability. In a randomized, controlled clinical trial, a treatment group (n = 9) received the Neuro-Developmental Treatment-based intervention protocol, whereas the preterm control group (n = 10) received an identical amount of nonspecific handling. A group of infants born at term (n = 8) also received no intervention. Outcome was assessed by testers blind to preterm group assignment using the Neonatal Behavioral Assessment Scale and a Supplemental Motor Test designed to assess quality of postural control. The term control group performed significantly better than either of the preterm groups on the motor performance cluster of the Neonatal Behavioral Assessment Scale, and the preterm control group performed better than other groups on the autonomie regulation cluster. On the Supplemental Motor Test assessment of postural control, the preterm treatment group outperformed both control groups on spontaneous behavior items and the preterm control group on elicited activity items. Preterm groups did not differ in average weight gain. A Neuro-Developmental Treatment-based intervention was efficacious in improving postural control in infants born prematurely but did not significantly improve tone, behavioral state, reflexes, or autonomie regulation.

Examination of the item structure of the Alberta infant motor scale.

Purpose The Alberta Infant Motor Scale (AIMS) is a screening tool for identifying delayed motor development from birth to 18 months of age. The purpose of this study was to examine the psychometric structure of the AIMS, including the hierarchical scale of items and the precision for measuring infant ability at different ages. Methods Ninety-seven infants with varying degrees of risk of developmental disability were recruited from three hospitals or from the community in the Chicago metropolitan area. Infants were tested on the AIMS at three, six, nine, and 12 months of age. The hierarchical structure and the range and distribution of item difficulty on the AIMS were analyzed using Rasch psychometric analysis. Results The Rasch analysis confirmed that items for each of the four testing positions (supine, prone, sitting, and standing) were arranged in increasing order of difficulty, but a ceiling effect was present. Gaps exist at six ability levels, indicating low precision of measurement for differentiating among infants after about nine months of age. Conclusions The AIMS shows a ceiling effect, measures infant ability best from three to nine months of age, and has few items available for discriminating among infants after they pass the controlled lowering through standing item. Clinical impressions should be drawn with caution at ages when the precision of measurement is low.

The Test of Infant Motor Performance: Reliability in Spinal Muscular Atrophy Type I

Purpose: The aim of this article was to determine reliability of the Test of Infant Motor Performance (TIMP) in infants with spinal muscular atrophy, type I (SMA-I). Methods: Interrater reliability training was undertaken by 17 physical therapist evaluators using 6 infants with hypotonia and weakness (5 videotaped, 1 live). Eight trained evaluators then conducted a test-retest reliability study at their own center, performing 2 tests approximately 1 month apart on each of 11 infants with genetically confirmed SMA-I (5 boys, 6 girls; age range 37–501 days; 3 on pulmonary support). Results: The interrater reliability training session had an overall weighted &Kgr; of 0.61 (95% confidence interval 0.59–0.63). For the test-retest reliability study, the intraclass correlation coefficient for the TIMP Total Score was 0.85 (95% confidence interval: 0.54–0.96). The test scores were not significantly different between the 2 sessions (Bradley-Blackwood test was nonsignificant). Conclusion: TIMP scores can be reliably obtained in infants with SMA-I.

Longitudinal Performance of Infants with Cerebral Palsy on the Test of Infant Motor Performance and on the Alberta Infant Motor Scale

Understanding the natural history of development in children with cerebral palsy (CP) is important for studying the consequences of early intervention. The purpose of this paper is to present results on the Test of Infant Motor Performance (TIMP) from 0-4 months of age and on the Alberta Infant Motor Scale (AIMS) from 3 to 12 months of age in a group of infants later diagnosed as having CP. Ages at which infants with CP were first recognized as having delayed motor performance on each instrument and the stability of performance over time are presented. Clinical implications for using both instruments are discussed.

Test-retest reliability of the Test of Infant Motor Performance

The purpose of this study was to 1) assess test-retest reliability of the Test of Infant Motor Performance (TIMP) over a three-day period and 2) compare the effect on test-retest reliability of the TIMP of using same or different raters on the two test occasions. One hundred sixteen pairs of tests w

Population-based age standards for interpreting results on the test of motor infant performance.

Purpose: The goals of this study were establishment of age standards for the Test of Infant Motor Performance (TIMP) and evaluation of possible group differences based on sex, medical risk for poor developmental outcome, and race/ethnicity. Subjects: Subjects were 990 infants with a range of risk for poor outcome from 11 geographic locations across the United States that were recruited to reflect the distribution of race/ethnicity in the US population of low birth weight infants. Methods. Between 67 and 97 infants were tested in each two-week age range from 34–35 weeks’ postconceptional age through 16–17 weeks after term. Boys made up 52% of the subjects. Fifty-eight percent of the sample was white, 25% black, and the remainder were of other ethnicities. Scores for all infants in each age group were averaged to form age expectations for each two-week period. Multiple regression was used to explore the effect on TIMP scores of sex, risk, and race/ethnicity. Results: Means ranged from 49 (standard deviation = 15) at 34–35 weeks’ postconceptional age through 120 (standard deviation = 16) at 16–17 weeks after term. High-risk infants scored significantly lower than other infants (beta = −0.133, P < 0.0001). Latino infants scored lower than infants of all other ethnicities (beta = −0.052, p < 0.006). Performance did not differ by sex. Conclusions/Clinical Implications: These standards for performance on the TIMP can be used to identify infants with delayed motor development.