BACKGROUND: Inexpensive, head-fixed computer displays are now available that subjects can wear during locomotion. HYPOTHESIS: Viewing a head-fixed visual display will change the characteristics of rotational head perturbations during natural walking. METHODS: Using a 3-axis angular rate sensor, we measured head rotations during natural or treadmill walking, in 10 normal subjects and 2 patients with deficient vestibular function, as they attempted to view (A) a stationary target at optical infinity; and (B) a target at a distance of 20 cm rigidly attached to the head. RESULTS: Normal subjects and patients showed no significant change in the predominant frequency of head rotations in any plane (ranging 0.7-5.7 Hz) during the two different viewing tasks (p > 0.1). Mean peak head velocities (ranging 6-36 degrees.s-1) also showed no difference during the two viewing conditions except in the yaw plane, in which values were greater while viewing the near target (p < 0.005). Predominant frequencies of head rotations were similar in the pitch plane during natural or treadmill walking; however, peak velocities of pitch head rotations were substantially greater during natural walking (p < 0.05). One vestibular patient showed modest increases of head velocity during natural walking compared with normal subjects. CONCLUSIONS: Rotational head perturbations that occur during natural walking are largely unaffected when subjects view a head-fixed target. There is need to study how such perturbations, which induce vestibular eye movements, affect vision of head-fixed displays.
BACKGROUND: Inexpensive, head-fixed computer displays are now available that subjects can wear during locomotion. HYPOTHESIS: Viewing a head-fixed visual display will change the characteristics of rotational head perturbations during natural walking. METHODS: Using a 3-axis angular rate sensor, we measured head rotations during natural or treadmill walking, in 10 normal subjects and 2 patients with deficient vestibular function, as they attempted to view (A) a stationary target at optical infinity; and (B) a target at a distance of 20 cm rigidly attached to the head. RESULTS: Normal subjects and patients showed no significant change in the predominant frequency of head rotations in any plane (ranging 0.7-5.7 Hz) during the two different viewing tasks (p > 0.1). Mean peak head velocities (ranging 6-36 degrees.s-1) also showed no difference during the two viewing conditions except in the yaw plane, in which values were greater while viewing the near target (p < 0.005). Predominant frequencies of head rotations were similar in the pitch plane during natural or treadmill walking; however, peak velocities of pitch head rotations were substantially greater during natural walking (p < 0.05). One vestibular patient showed modest increases of head velocity during natural walking compared with normal subjects. CONCLUSIONS: Rotational head perturbations that occur during natural walking are largely unaffected when subjects view a head-fixed target. There is need to study how such perturbations, which induce vestibular eye movements, affect vision of head-fixed displays.
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NASA Discipline Neuroscience; Non-NASA Center
Authors: Yanning H Han; Arun N Kumar; Millard F Reschke; Jeffrey T Somers; Louis F Dell'Osso; R John Leigh Journal: Exp Brain Res Date: 2005-05-11 Impact factor: 1.972
Authors: Michael C Schubert; Americo A Migliaccio; Richard A Clendaniel; Amir Allak; John P Carey Journal: Arch Phys Med Rehabil Date: 2008-03 Impact factor: 3.966