The purpose of this thesis was to compare the contributions of attentional resources relevant to postural control between fall-fearful and non-fearful older adults. Levels of postural challenge and instructions of task prioritization were manipulated to obtain this goal. Results indicated that fall-fearful subjects demonstrated a reorganization of attentional resources when challenge to upright standing was imposed. Additionally, only non-fearful subjects demonstrated flexibility in the prioritization of the cognitive task. However both fall-fearful and non-fearful subjects demonstrated flexibility in the prioritization of the postural task. Findings suggested that fall-fearful older adults reorganize the allocation of attentional resources differently than non-fearful counterparts, potentially placing them at greater risk for falling as their awareness of the external environment and threats to balance may be compromised. / xii, 80 leaves : ill. ; 29 cm

The purpose of this thesis was to investigate the influence of postural anxiety on the capacity for Flexible Resource Allocation (FRA) among younger (YA) and older adults (OA). Two experiments were conducted to explore (a) the influence of heightened postural anxiety on the flexible allocation of attention among OA and (b) the influence of concurrent postural challenge and postural anxiety on FRA among YA. Participants performed a postural task concurrently to a cognitive task according to three instructional sets directing task priority. Experiment one revealed that FRA was compromised among OA during circumstances of heightened anxiety. This capacity however, remained available among YA. Therefore, for the second experiment I varied the support surface to explore whether the capacity for FRA could be sustained when posture was challenged beyond static stance. Results indicated that YA altered cognitive task performance according to instructional set without compromising postural stability. These findings suggest that even when posture is challenged during heightened postural anxiety, YA maintain the capacity to automatically allocate attention to a postural task while performing a secondary task. Conversely, it seems that heightened postural anxiety strengthens the attentional bias to posture and subsequently compromises FRA among OA. Overall, results from this thesis suggest that the capacity for FRA is age and situation dependent. / xi, 107 leaves : ill. ; 29 cm

The effect of anxiety on motor learning during a balance relevant task was investigated. Twenty participants (mean age 22.0 ± 2.7 years) were randomly divided into groups that completed the task whilst standing directly on the platform or on 9cm high pedestals, thus constructing Non-Anxious (NA) or Anxious (A) environments. Participants trained for 36 trials in a continuous, pseudo-random oscillating balance task consisting of pseudo-random amplitude translation at 0.5Hz for 45 seconds each on Day 1 and returned for Retention and Transfer tests on Day 2. Motor performance was impaired by training in an anxious environment and this effect persisted across retesting in both non-anxious and anxious environments. Anxiety also tended to further impair transfer of motor performance improvements to a non-anxious environment. These findings have implications for the success of balance training programs in patients who are anxious or afraid of falling. / ix, 103 leaves : ill. ; 29 cm