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Thesis (D.P.T.Sc.)--University of California, San Francisco, 2009. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3472. Adviser: Kimberly Topp.

Thesis (Ph.D.)--University of California, San Francisco, 2009. / Source: Dissertation Abstracts International, Volume: 70-04, Section: B, page: 2198. Adviser: Nancy A. Stotts.

Trunk control is intriguing because trunk muscles must meet multiple requirements during the performance of everyday tasks (e.g., balancing, locomotion, musical instrument playing, reaching, trunk bending, vocalizing). A unique feature of trunk muscles is that they often participate in simultaneous trunk movement and breathing-related behaviors. This study was designed to test the hypothesis that two voluntary task-specific muscle activity patterns could combine linearly when both tasks activate the same muscles. Surface electromyograms (EMG) were recorded from four trunk sites (upper and lower lateral abdominal, medial and lateral back) during the performance of a trunk task, pulsed expiration task, and combined task (hunk + pulsed expiration task). The trunk task varied across four experiments, and included a static holding task or a uni-directional movement task in both flexion and extension directions. The expiration task was constant. Selected task variables (lung volume, movement amplitude and duration, expiratory target pressure) were consistent across all tasks. For each EMG site, a linear prediction (predicted EMG trace) was calculated from the mathematical addition of the task-specific EMG recorded during the individual trunk and expiration tasks. This linear prediction was compared to the actual muscle activity recorded during the combined task (measured EMG trace) and a point-to-point correlation was performed on the two traces to determine how closely they matched. Findings showed that in just over half the comparisons, the combined muscle activity pattern (measured EMG trace) was the same as a linear addition of each individual muscle activity pattern (predicted EMG trace). Such linear addition implies that two sets of descending command signals reach motoneuron pools essentially unmodified, and that motoneurons supplying trunk muscles may be specially organized to receive dual and simultaneous voluntary neural drive. In the remaining comparisons, the EMG activity for the two individual tasks, were superimposed, but not linearly. This finding suggests that although individual muscles are activated as a unit, selected muscles may be modified by sensory feedback. This flexibility allows the nervous system to take advantage of a muscles mechanical effectiveness and to adapt to environmental constraints without having to reconfigure or construct a new set of instructions.

There is a lack of knowledge on the effect of an oral stimulation program, prior to the introduction of oral feeding, in preterm infants who are less than 30 weeks gestational age. The objective of this study was to assess whether a prefeeding oral stimulation program enhances the oral feeding performance of preterm infants born between 26--29 weeks gestational age. / A randomized trial was carried out. Thirty-two infants completed the study. The experimental group received the oral stimulation program. The control group received the sham stimulation program. The outcome measures were defined as: time to attain independent oral feeding, overall intake, rate of milk transfer (ml/min), maturation of sucking and length of stay at the hospital. / The experimental group attained independent oral feeding faster and demonstrated consistently greater overall intake and rate of milk transfer than the control group, as their oral feeding regimen was advanced. These findings are attributed in part to a more mature sucking pattern observed in the experimental group. There was no difference in length of stay at the hospital between the two groups. / This study demonstrates that an early oral stimulation program can enhance the development of sucking. This supports the concept that development of sucking is dependent on both physiological maturation and external experiences. Such a program may be included in neonatal developmental care plans because it is safe, simple and inexpensive.

The purpose of this project was to develop a reliable and valid battery for the assessment of spatial orientation skills (SOS) in persons with Alzheimer's disease (AD). The battery, comprised of 13 subtests, was administered to 97 normal control subjects, 25 subjects with early AD and 10 with late AD. The test-retest reliability of the battery was based on the test results of 33 normal control subjects and 25 early AD subjects. Inter-rater reliability was determined using four trained raters who evaluated 27 normal control subjects and the same 25 early AD subjects. Content validity was established using a panel of six experts and construct validity was determined by comparing the performance of the normal control and early AD groups. To establish criterion validity, the Global Deterioration Scale (GDS) was used as the criterion. For the AD group, eight subtests demonstrated acceptable test-retest and inter-rater reliability coefficients (ICC $ ge$.70). For the control group, three subtests had acceptable test-retest coefficients and four had acceptable inter-rater coefficients. The internal consistency of the battery was acceptable as shown by overall Cronbach's alpha of.86 for AD subjects and.72 for control subjects, and was further analyzed using factor analysis which yielded five factors. Logistic regression provided evidence for good construct validity. Scores on the SOS subtests were able to differentiate the three groups of subjects established on the basis of the GDS scores (GDS 1 and 2, GDS 3 and 4, and GDS 5). A preliminary shortened version of the battery was developed using six subtests which demonstrated high test-retest and inter-rater reliability. The performance of subjects with AD on the battery is discussed with respect to its implications for the theoretical basis and clinical assessment of spatial orientation in AD.

The present study investigated the reorganization of the somatosensory cortex in kittens following T12 spinal cord transection at 2 weeks of age. Multiunit electrophysiological methods were used to map the somatosensory cortex of kittens at 3, 6, and 9 weeks after the transection. The entire reorganized cortical region was driven by substitute cutaneous inputs at 3 weeks after spinal cord transection. This level of cortical responsiveness remained the same throughout the other two time periods studied. Also, throughout the 9 weeks studied, the majority of the substitute inputs came from the trunk. A smaller percentage of the substitute inputs arose from the shoulder girdle and the forelimb region. A lack of somatotopic and topographic order was seen in the reorganized cortex of all experimental animals. Finally, trunk receptive fields displayed a wide variety of shapes, sizes and orientations not seen in the normal cortex.

When physical impairment impedes a driver's access to a vehicle's controls, adaptive equipment can compensate for functional loss. However, the impact of modifying automotive controls and the effectiveness of driver-training remain unclear. Of particular importance is the older driver's ability to integrate these adaptations. / This thesis comprises two studies comparing older and younger drivers' perceived workload when driving with adaptive devices. First, workload ratings in normal driving were compared to ratings while driving using hand-controls to activate the vehicle's pedals. Significant increases in workload were observed for younger and older drivers. The second study evaluated the effect of driver-training on workload, comparing ratings prior to and following three hours of training. Although training was effective in reducing workload, seniors' scores did not return to baseline levels as did the younger drivers', and gender differences were observed. Clinically, the studies support the need for training. Age and gender may impact training-response.

The primary objective of this study was to examine the modulation of prehensile forces in people with cerebral vascular accidents resulting in sensory deficits on the hand. A prehensile pinch force apparatus was constructed to measure the pinch forces employed when holding a manipulandum between the thumb and index finger, and to determine how these forces changed as a function of the direction of force applied to the hand by a motor connected to the manipulandum and the surface texture of the manipulandum (i.e. plastic, suede, sandpaper). Sensorimotor function was assessed in twelve experimental subjects (patients) and fourteen normal control subjects using a number of tests, including pressure sensitivity, static and moving two-point discrimination, a hand function test, a timed object-recognition and material-recognition test, and a test of pinch strength. On the tests of sensibility and hand function, but not of pinch strength, the experimental group had deficits on the hand contralateral to the cerebral lesion. For all subjects who could perform the prehensile pinch force test (PPFT), pinch forces were modulated with the forces applied to the hand, although most of the experimental subjects did not adjust their pinch forces to the surface texture of the manipulandum. These findings indicate that the PPFT holds promise as an objective measure of hand function.