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poster
Purpose: Infants exposed to polydrugs have been reported to have highfrequency tremors, jittery movement and neurological sequelae during thenewborn period. This study examined polydrug and control infants at onemonth of age using signal analysis techniques to explore these newbornclinical findings in older infants. Techniques were developed to quantifyoscillatory properties of limb movements. Infants were measured in threeexperimental conditions; 1) no stimuli: spontaneous movement 2) rattleshaken in front of infant 3) face-to-face interaction with femaleexaminer. Hypotheses: 1) polydrug exposed infants will demonstrate higherfrequency components in all limbs in comparison to control infants 2)these differences would be greatest in the spontaneous condition withrattle and face-to-face conditions showing lower and more regularfrequencies, as these conditions act to organize oscillatory movements.Subjects: The sample included 19 infants exposed to polydrugs and 21control infants. All infants were recruited from the same nurseries andwere free from neonatal sequlae related to adverse developmental outcome.Polydrug exposure was determined from urine assay of mother or infant.Control status was determined from meconium assay. Groups were matched onrace, maternal education and family income indexed as health insurancemethod of payment.Method: Infants were seated in a reclining infant seat which wassurrounded by black screens to eliminate extraneous stimuli. Data werecollected in three conditions. Infant arm, leg and head movements wererecorded using Peak Performance Technology motion system. Reflectivemarkers were secured to bands which were attached to the infants wrists,ankles and center of forehead. Markers were sampled and digitized at 60Hz. Fifty seconds of movement were digitized for each subject in eachcondition. Data were filtered with a 4th order Butterworth filter at 10Hz. Velocity, acceleration and resultant values were computed. First andsecond derivatives were computed from the resultant values. A powerspectral density (PSD) was computed from the fast Fourier Transform (FFT)of velocity and acceleration. Median and peak frequencies were computedfrom the PSD. Data was managed with MATLAB, Signal Processing Toolbox.Results: There were no differences in any variables between the polydrugexposed and control infants. There were significant differences amongconditions. Both median and peak frequencies from velocity data weresignificantly higher in the rattle condition in comparison to the othertwo conditions for left hand and foot. Some infants' left limb frequenciescorresponded precisely to the rattle frequency (5Hz).Conclusions: There was no evidence that the tremors, jitteriness and highfrequency movements reported for newborns exposed to polydrugs werepresent in one month old exposed infants. This study provides clearevidence that infant limb movement can be modified by external stimuli andthat the techniques we have developed are highly sensitive measures ofthese environmental effects.
poster
The effects of intrauterine cocaine exposure on neuromotorfunctioning remain unclear. Consistent empirical evidence for motordysfunction beyond the newborn period is lacking. One possible reason forthis paucity of findings is that most studies have utilized globalassessments of motor performance rather than precise, quantitative measuresof movement. One purpose of this longitudinal study was to use kinematicanalysis to describe the quantitative parameters and coordination ofreaching in prenatally cocaine exposed and unexposed infants at 7 and 15months. Because reaching is affected by specific task demands (e.g. demandsfor precise versus global movements) as well as object properties (e.g.size, distance) in relation to hand, we also evaluated the effect ofdifferent types of task demands on infant reaching parameters at each age. Method: 22 prenatally cocaine-exposed and 16 demographicallymatched, unexposed infants were observed at both 7 and 15 months. Exposurestatus was confirmed by meconium analysis. All infants were healthyfullterms and living in poverty. Exposed mothers significantly used morealcohol and cigarettes during pregnancy. Infants were seated at a cut-outwooden table next to the caregiver. Materials included 2 toys of similarsize: 1) a small, clear plastic box filled with unpopped popcorn and 2) atwo-part Lego doll and chair. Each toy was placed on the table withinreach of the infant at the infants' midline. In an additionalpresentation, the chair/doll toy was also suspended in front of the infantat the infants' shoulder height. Each toy presentation was made at least 5times. Infant reaches/actions with each toy presentation were videotapedby cameras placed in front of the infants and wall-mounted above and toeach side of the infant at 90 degrees orthogonal to each other. Reflectivespheres were placed on the infants' forehead, left wrist, right wrist, andon the top of each toy. Peak Performance was used to digitize thekinematic data at a sampling rate of 60 Hz and filtered at 5 Hz. Infants'reaches/actions were classified into 4 a priori 'Task Demand' categories:PRECISE (e.g., puts Lego doll on chair), EXCITE (e.g., throws box), INSPECT(e.g., examines box intensively with visual and manual exploration), andUNSUCCESSFUL (e.g., unsuccessful reaches which did not end in grasping orlifting the object). Kinematic outcome variables included: movement time(MT), movement units (MU), straightness of reach (ST), peak velocity (PV),and point of peak velocity (PPV). Results: Multivariate analysis of variance models (MANOVA) wereused to analyze the data. Exposure status was not related to any of thekinematic measures; consequently, the two groups were collapsed forsubsequent analyses. As expected, MT, MU, ST, and PPV decreased withinfant age. Significant effects of Task Demand were found for ST, PV, andPPV. As expected, reaches in the EXCITE category had significantly higherPV than those in the INSPECT category. Reaches of PRECISE category hadsignificantly lower PPV (longer deceleration phase) than those in theEXCITE and INSPECT categories. UNSUCCESSFUL reaches had higher PV, ST, andPPV than those in the other categories. Infants' reaches in the Suspendedcondition had higher ST and PV than in the Table condition. Conclusion: The early compromising effects of prenatal cocaineexposure on infant motor performance reported clinically were not observedin this study. Both exposed and unexposed infants, like adults, organizetheir reaching and actions with objects in accordance with the demands ofthe task. Moreover, similar age-related changes in reaching parameters wereobserved in each group. Future studies of infant reaching using kinematictechniques must consider the important influence of task constraints oninfant performance.
poster
Introduction: Assessment of motor performance for children with gross motor delay has diagnostic value, and is often essential to document the need for intervention services. Numerous instruments exist for this purpose, but they are time consuming, and generate normed comparison scores that do not provide immediately accessible information on the child's actual level of performance. Moreover, some argue that normed assessments are inappropriate for tracking performance changes of children with structural disabilities. For these reasons, the BAMF was developed specifically for infants and children with disabilities. Purpose: The BAMF is a ten point motor skill assessment designed for very rapid identification of motor performance level, similar to the APGAR, using hierarchically ordered motor tasks in gross, fine, and oral motor domains. The objective of the present study was to examine the reliability and concurrent validity of the gross motor scale of the BAMF with 1) Peabody Developmental Motor Scales (PDMS), 2) Childhood Health Assessment Questionnaire (CHAQ), 3) formal gait analysis, and 4) selected manual muscle test scores, to determine if it is a reliable, valid, and cost effective tool for rapid gross motor assessment. Participants and Procedures: 40 infants and children (24 girls, 16 boys) with types III and IV osteogenesis imperfecta, ages 5 mo - 17 years, participated in age-appropriate evaluations (PDMS, CHAQ, gait analyses, muscle tests and BAMF) as part of an osteogenesis imperfecta research program for infants and children from birth to 18 years at the National Institutes of Health. Twenty health professionals scored 10 children for BAMF reliability. For concurrent validity, the BAMF, PDMS, CHAQ, Kendall's ten point scale for muscle strength (mmt), and gait analysis using a modified Vicon VX system were completed at the same visit. ICCs, Spearman correlations, and forward selection multiple regression were used to determine the reliability of the BAMF, and to identify relationships between BAMF scores and the PDMS, CHAQ, mmt, and gait parameters.Results: BAMF interrater reliability: ICC (1,1) .996; intrarater reliability ICC (3,1) 1.00. Statistically significant relationships were identified between BAMF and the PDMS (r.95, p*), CHAQ (r-.84, p.001), gait speed (r.68, p*), stride length (r.71, p*), duration of double limb support (r-.40, p.03), and number of weak muscles (r -.74, p*). For criterion variable BAMF, using SAS forward selection multiple regression (FSMR) at alpha.05, stride length was highly predictive (R2.8137, F', p*), followed by gait speed (R2.0877 incremental variance, F17, p.0004). In a separate FSMR analysis for BAMF in relation to individual muscle groups, only hip abduction (R2.4821, F22, p*) was entered into the model. Conclusions: The BAMF is highly reliable, demonstrates acceptable concurrent validity with formal gait assessment, and is significantly correlated with gross motor development and muscle strength in infants and children with osteogenesis imperfecta. These findings suggest it may be useful for baseline and longitudinal determinations of gross motor capability when a rapid, age independent, and cost effective measure is appropriate. *p.0001
poster
Objectives: Osteogenesis imperfecta (OI) is a heritable connective tissue disorder characterized by muscle weakness, brittle bones, short stature and long bone bowing. Infants and children with moderate to severe OI have locomotor limitations, and their behavioral style may play a role in determining motor performance outcomes. For this reason, temperament of children with OI was assessed in order to 1) compare their temperament to that of typical children, 2) investigate the relationship between temperament and physical performance, and 3) investigate the relationships among parental overprotection, temperament, and physical performance. Methods: Carey Temperament Scales and the Vulnerable Child/Overprotecting Parent Scale (VCOPS) were completed by mothers of 35 children ages 1-12 years with Type III or IV OI. Each child's physical performance was evaluated using the Brief Assessment of Motor Function (BAMF) (range: head elevation -> running). Temperament data from the 35 children were standardized using z-scores, then the z-test was used to compare children with OI to the norms for all nine subscales of temperament (activity, adaptability, approach, mood, intensity, distractability, persistence, threshold, and predictability). Relationships to performance were evaluated using Spearman's rank correlations and forward selection multiple regression. To account for disease-related constraints on performance, indicators of biological severity (such as radiographic inhomogeneity of bone), clinical mediators (including number of fractures in the preceeding year), and anthropometric ratios were included in the a!nalyses.Results: No significant differences were identified between temperament of these children and their nondisabled peers, with the exception of significantly lower activity scores (adjusted p<.001). Statistically significant relationships were identified between activity and mood (r.47,p.004), adaptability (r.46,p.005), and intensity (r.40,p.02). Mood predicted activity (R2.20, F6.67, p.016). Activity also correlated with ratio of head circumference to body height (r-.45,p.02) and number of fractures in the preceeding year (r-.35,p.05). Persistence (r-.48,p.003), approach (r-.34, p.05) and activity (r.40, p.02) correlated significantly with motor performance (BAMF). Ratio of chest circumference to body height and biological severity rating predicted 66% of the variance for BAMF (F .34 p.0000). No significant relationships were identified between VCOPS and either temperament or BAMF.Conclusions: Temperament of children with types III and IV OI differs from age-based norms only in the activity domain. These data suggest that the activity associated with temperament is constrained by structural and clinical factors, implying that disease may influence the child's expression of the activity domain of temperament. Since motor performance is significantly related to activity, persistence with tasks, and approach responses to new people and events, considering temperamental style may increase the infant's or child's ability to benefit from rehabilitation interventions.
poster
Developmental change in spontaneous movements of five low-riskpreterm infants were studied longitudinally after their birth until 52weeks postmenstrual age. Each subject was videotaped at least every 4weeks from the postmenstrual age of 33-36 to 53-59 weeks. The video camerawas positioned approximately one metre above the infants. During theobservation period, the infants were naked and free to move in the supineposition. Actograms of the infants' movements were made by transcribingthe videotaped recordings. In the actograms, the categories of spontaneousmovements of Cioni et al. (1989) were employed. In addition to these, thefollowing seven categories were used: hand-mouth contact, hand-facecontact, hand-head contact, hand-body contact, hand-hand contact, hand-legcontact and foot-foot contact. All of these categories except H-M-C weredefined as the contact of two parts of the body. H-M-C was defined as beingeither the fingers and / or thumbs in the mouth. When the subjects showedno movements, their postures were outlined in the actograms. From the actograms of five infants, it was found that thespontaneous movements, such as head rotation, hand-face contact andfoot-foot contact were frequent in the preterm period. The occurrence ofthese spontaneous movements decreased drastically around the second monthafter the expected date of delivery, and then increased around the fourthmonth. This increase reached the level of the preterm period. Movements,such as startle, cloni and tremor, which had been also observed in thepreterm period, decreased after the term period and did not later increaseagain. Only general movements (GMs) continued to appear while otherspontaneous movements decreased. The above mentioned spontaneous movements are in the preterm periodstrongly influenced by GMs, because most of them occurred during GMs. Toclarify the relationship between the various spontaneous movements and GMs,we determined whether these spontaneous movements are a part of GM or not. In the preterm period various spontaneous movements occurred in addition toGMs. Thereafter, GMs still continued to be present, whereas most of theother spontaneous movements decreased. This means that the nature of GMschanged in this period. Hopkins and Prechtl (1984) characterized the twophases of GM as changing from a writhing quality into a fidgety quality,corresponding with the decrease of other spontaneous movements. In thesecond phase (fidgety quality), the touching movements can be regarded asbeing independent of GM. According to Einspieler et al. (1997) GMsgradually disappear at about 60 weeks of postmenstrual age,. Moreover, itis well known that the touching movements become voluntary movements. Itmight be speculated that after their increase, the spontaneous movementssuch as head rotation, hand-face contact and foot-foot contact graduallybecome part of the independent repertoire of the infants' movements, thusdifferentiating them from GM.
poster
Infants born preterm with a Grade III or IV intraventricular hemorrhage(IVH) are at risk for developmental delays and cerebral palsy. By parentalreport, these infants rarely are placed in the upright vertical position andearly stepping is not encouraged. In a previous study (Heriza, 1992), nineinfants born preterm with a Grade III or IV hemorrhage demonstrated delay invertical weight bearing and stepping. Kinematic and behavioral analysesindicated poor coordination within a single limb and between limbs. Thispilot study addressed the effects of treadmill training on stepping in asingle infant born at 29 weeks gestation with a birth weight of 1161 grams.A Grade III hemorrhage was documented on the left with mild bilateralhydrocephalus. Treadmill training started at 6 mos corrected age (CA).Training was conducted 3x/week at a treadmill speed of 15 cm/s. Traininglasted 2 min 20s followed by a 2 min break and a second period of trainingfor 2 min 20s. Weekly training was discontinued after 17 wks (10 BC CA) whenthe infant consistently produced alternating steps on the treadmill threetimes consecutively. A one min 30s scalar probe session was videotapedweekly during training. The probe was divided into five intervals of s:stationary, 10 cm/s, 15 cm/s, 20 cm/s, and stationary. Post training, probesessions continued every two weeks until the infant took three independentsteps (16 BD mos CA). The last 15s of the videotapes were coded usingpredetermined criteria for time of initiation of swing and initial contactand step type (double, single, parallel, alternating). Phase lags werecalculated as a measure of interlimb coordination; standard deviations (SDs)of the phase lags were calculated as a measure of variability.The infant took no steps when the treadmill was stationary. When thetreadmill was on, the infant took steps at all three speeds. There was anincrease in number and types of steps with increasing speed. The mean numberof alternating steps, pooled over speed, increased with training and age; by10 mos CA alternating steps predominated. At the end of the training period,alternating steps were preferred at all three speeds. By the end of theprobe sessions, only alternating steps were taken at all three speeds.During training, there was a clear trend toward a .5 phase lag; by 11 mosCA, phase lags were consistently around .5. SDs of phase lags initiallyshowed wide ranges of variability (.22 - .65) and then settled into less variability (.25 -.31) Treadmill stepping appeared to entrain alternating steps for this infantwith a grade III hemorrhage. With training and age, the infant stepped moreon the treadmill, alternating steps became dominant, and coordinationbetween the two legs became more symmetrical. Studies need to be conductedwith atypical infants to confirm that treadmill stepping is a stabilizingattractor for alternating stepping. Optimal time to start training alsoneeds to be elucidated.
poster
Studies of the infant preterm conditions of life has first consisted in adescription of the effects of the sensory stimulations presented to thebaby placed in the incubator. These effects were characterized as beingover-stimulating, lower-stimulating or dystimulating (Turkewitz et Kenny,1985 ; Field, 1991). Today, the studies conducted in this field try toinvestigate more precisely how preterm infants process these stimulationsand how they can be helped to cope with it. As noticed by Drotar (1997),this question is center in the field of pediatric psychology. Studies about pain or stress conducted in infants have to deal with twomajor difficulties : 1) definition of the stressfull properties of thesituation, 2) choice of relevant behavioral cues. We decided, in accordwith Gunnar's work, to relate behavioral cues and cortisol level measuredin saliva sample. However, first attemps clearly provided evidence of theextreme difficulty in measuring and analysing corticol level in preterminfants. Corticol sampling constitutes by itself a stressfull situation.Moreover, the sample contains various food substances and medications.Consequently, the present project has been conducted in order tosimultaneously record, cardiac rythm, respiratory rythm and instantaneousskin temperature of the infant preterm placed in incubator. Resultsobtained with 6 babies (born before 33 weeks of G.A) indicate that thetemperature differential recorded between the abdomen and the foot issystematically modified by the introduction of a stressfull event such as anoise coming from a vibror placed outside the incubator, in the top of it.Analysis of the various psychobiological cues indicate that differentpattern of responses are observed. when the infants are directly exposed,inside the incubator, to less stresfull event such as music (piano) or odor(nonanoEFque acid). These patterns can be interpreted in terms of itspacifying effect.The second part of the project compares actimetric and calorimetricpatterns according to the infant's vigilance and to the various events thatoccured in the incubator, in particular auditory stimulations related tothe various nurse-care incoming on a 24 hours periods. Babies arecontinuously videotaped. Motor activity is recorded via an actimeter.Temperature is recorded by a coetaneous thermistor. Behavioralmodifications occuring during the 24 hours are compared according to thecorrected infant age and at a week of interval (first week of life comparedto the second week of life). Results show that preterm infants differentlyprocess social sounds (human voice) and artificial sounds. Babies do notseem to habituate in the same way to each stimulation. Current recordingsconcern babies demonstrate early neuropathological signs. These knowledgeabout infants placed in care situation help to improve clinicalinfants'examination.