published_or_final_version / Medicine / Doctoral / Doctor of Philosophy

The stiff-knee gait pattern of children diagnosed with cerebral palsy (CP) is assumed to be caused by spasticity of the quadriceps which interferes with knee flexion normally occurring during the swing phase of walking. In current clinical practice, the ability to assess quadriceps spasticity is limited by the lack of an objective and reliable test that discriminates the role spasticity plays in functional limitations. The primary purpose of this series of studies was to assess the pendulum test as an objective measure of quadriceps spasticity. The first study assessed the reliability of the pendulum test. Moderate to very high between day reliability for all thirteen measures of the pendulum test were found. The second study assessed the discriminant ability of the pendulum test to correctly identify a stiff-knee gait pattern. Because most clinicians do not have access to a three dimensional motion analysis system, the third study assessed the reliability and accuracy of visual observation of the pendulum test. Sixty-eight children with a primary diagnosis of cerebral palsy participated. A three-dimensional motion analysis system was used to measure the subjects knee motion while walking, and performing the pendulum test. Spasticity of the quadriceps was also assessed using traditional clinical measures i.e., the modified Ashworth scale (MAS), and the Ely tests. Forty-seven percent of the variance in the stiff-knee gait pattern was explained by a regression model using the pendulum test and traditional clinical measures. The only significant measure in the regression model was the magnitude of knee motion occurring during the first swing of the pendulum test (A1). Discriminant analysis revealed the A1 measure correctly classified 77% of the subjects knee-gait pattern. Four observers demonstrated moderate accuracy and repeatability in estimating A1 value. The visual assessment of A1 correctly classified 72-76% of the subjects knee-gait pattern with no prior knowledge of the subjects gait. This series of studies demonstrated the pendulum test is an objective, repeatable measure of quadriceps spasticity. A negative pendulum test (indicated by an A1 value greater than 45 degrees) is more useful for ruling out a stiff-knee gait pattern compared to the traditional clinical measures.

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The purpose of this study was to elucidate the indifferent passive behavior described in persons with right cerebral hemisphere dysfunction (Bear & Fedio, 1977; Critchley, 1966; Denny-Brown, Meyer & Horenstein, 1952). The process of caring for another person encompasses an interpersonal relationship with that person. Passive behavior may interfere with that relationship (Fried, 1970), and therefore jeopardize care. This correlational descriptive study was based on an explanatory model which included hemispheric side of lesion, attention, neglect of extrapersonal hemispace, passive behavior, and mood/emotion. The following indicators of outcome variables were used: attention--bilateral skin conductance level and skin conductance response; neglect--line bisection and cancellation tasks; passive behavior--a modification of Mays' (1973) Activity Passivity Scale; mood/emotion--the anxiety and depression subscales of Kellner and Sheffield's (1973) Symptom Rating Test. The sample comprised 10 persons with a single right hemisphere stroke and 10 persons with a left hemisphere stroke. The strength of the relationships among the variables was assessed only for persons with right hemisphere stroke. The data from this sample support some of the theorized links in the conceptual model, but not others. The predicted positive relationship between right hemisphere stroke and neglect, and the negative relationship between right hemisphere stroke and anxiety were demonstrated (r = .3177 and r = -.4353, respectively). The predicted negative relationship between right hemisphere stroke and attention was not demonstrated. Unexpected significant positive correlations existed between right hemisphere stroke and estimates of attention from the left hand (r = .3111 to r = .4472). No demonstrable relationship existed between right hemisphere stroke and passive behavior. Another unexpected finding was that the scale to scale and part to whole correlations for the concepts mood/emotion and passive behavior were strikingly different for the two groups. The fact that the two groups of subjects did not interpret the contents of the two scales similarly indicated that persons with right hemisphere dysfunction view the world quite differently from those with left hemisphere dysfunction. Appreciation of these differences may allow formulation and implementation of effective care plans which will reduce frustration in both client and caregiver.

Differences in cerebral lateralization of verbal and nonverbal stimuli between left- and right-handed good readers and left- and right-handed reading-disabled children were examined. The study utilized the dichotic listening paradigm and examined the effects of directed attention on the processing of consonant-vowel (CV) and tonal stimuli by the four groups. The sixty subjects included fifteen right-handed good readers (eleven females and four males, mean age 10-3), fifteen left-handed good readers (eight females and seven males, mean age 10-5), fifteen right-handed reading-disabled children (six females and nine males, mean age 10-5), and fifteen left-handed reading-disabled children (four females and eleven males, mean age 10-8). All left-handed subjects had sinistral relatives. A three-factorial analysis of variance resulted in a significant left ear advantage (LEA) for tonal stimuli across all directed attention conditions for all groups. When presented with CV stimuli, the right-handed good readers produced a significant right ear advantage (REA) across all attentional conditions. The left-handed good readers and left-handed reading-disabled children were left ear (LE) dominant in the free recall and directed left conditions but produced a shift toward the right ear (RE) during the directed right condition. Right-handed reading-disabled children demonstrated a REA during free recall and directed right but were able to direct attention to the LE in the directed left condition. The study provided initial findings on the auditory processing of simple tonal stimuli among anomalous groups of children and documented the strong LEA found in previous studies of adult subjects. Verbal processing results for right-handed good readers and reading-disabled children confirmed previous findings with these populations. Reversed verbal processing (right hemisphere) was documented in both left-handed groups in two of the experimental conditions. The results provide additional support for the structural theory of lateralization and suggest reversed or bilaterialized processing abilities for language in strongly left-handed good reader children. Components of the attentional bias model are necessary to explain the effects of directed attention on the auditory perceptual asymmetry found in the reading-disabled groups.

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