Effects of inertial load and cervical-spine orientation on a head-tracking task in the alert cat

ABSTRACT Introduction Neck pain among rotary-wing aviators has been established as an important issue in the military community, yet no U.S. Army regulation defines exactly what cervical spine range of motion (CROM) is adequate for flight. This lack of regulation leaves flight surgeons to subjectively determine whether an aviator affected by limited CROM is fit to maintain flight status. The U.S. Army Aeromedical Research Laboratory is conducting a study among AH-64 and UH-60 pilots to define CROM requirements in simulated and actual flight using optical head tracking equipment. Presented here is a preliminary analysis of head position data from a pilot and co-pilot in two AH-64 missions. Methods Maintenance data recorder (MDR) files from two AH-64 missions were provided by the Apache Attack Helicopter Project Management Office. Data were filtered down to three-dimensional pilot and co-pilot head position data and each data point was analyzed to determine neck posture. These neck postures were then categorized as neutral, mild, and severe for flexion/extension, lateral bending, and twist rotation postural categories. Results Twist rotation postures reached 90 degrees, particularly early in the flight; additionally, a few instances of 90-degree lateral bends were observed. Co-pilots spent more time than pilots in mild and severe twist rotation posture for both flights. Co-pilots also spend a high percentage of time in mild flexion and twist rotation. Conclusion This investigation provides a proof of concept for analysis of head tracking data from MDR files as a surrogate measure of neck posture in order to estimate CROM requirements in rotary-wing military flight missions. Future studies will analyze differences in day and night flights, pilot versus co-pilot CROM, and neck movement frequency.

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New AAC Access Strategy for Gesture Tracking: A Technical Note

Perspectives on Augmentative and Alternative Communication ◽

10.1044/aac21.1.11 ◽

2012 ◽

Vol 21 (1) ◽

pp. 11-16 ◽

Cited By ~ 1

Author(s):

Susan Fager ◽

Tom Jakobs ◽

David Beukelman ◽

Tricia Ternus ◽

Haylee Schley

Keyword(s):

Augmentative And Alternative Communication ◽

Technical Note ◽

Head Tracking ◽

Alternative Communication ◽

Access Methods ◽

Cord Injury ◽

Physical Limitations ◽

Gesture Tracking ◽

Communication Needs ◽

Tracking Device

Abstract This article summarizes the design and evaluation of a new augmentative and alternative communication (AAC) interface strategy for people with complex communication needs and severe physical limitations. This strategy combines typing, gesture recognition, and word prediction to input text into AAC software using touchscreen or head movement tracking access methods. Eight individuals with movement limitations due to spinal cord injury, amyotrophic lateral sclerosis, polio, and Guillain Barre syndrome participated in the evaluation of the prototype technology using a head-tracking device. Fourteen typical individuals participated in the evaluation of the prototype using a touchscreen.

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Clinical Update: Evaluation of the Cervical Spine

Guides Newsletter ◽

10.1001/amaguidesnewsletters.1998.janfeb04 ◽

1998 ◽

Vol 3 (1) ◽

pp. 6-7

Author(s):

Robert H. Haralson

Keyword(s):

Cervical Spine

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Motion Analysis of the Cervical Spine

Guides Newsletter ◽

10.1001/amaguidesnewsletters.2004.sepoct01 ◽

2004 ◽

Vol 9 (5) ◽

pp. 1-11

Author(s):

Patrick R. Luers

Keyword(s):

Cervical Spine ◽

Intervertebral Disk ◽

Radiographic Evaluation ◽

Ligamentous Injury ◽

Pattern Of Injury ◽

Motion Segment ◽

Single Pattern ◽

Compensatory Motion ◽

Loss Of Motion ◽

Flexion And Extension

Abstract The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fifth Edition, defines a motion segment as “two adjacent vertebrae, the intervertebral disk, the apophyseal or facet joints, and ligamentous structures between the vertebrae.” The range of motion from segment to segment varies, and loss of motion segment integrity is defined as “an anteroposterior motion of one vertebra over another that is greater than 3.5 mm in the cervical spine, greater than 2.5 mm in the thoracic spine, and greater than 4.5 mm in the lumbar spine.” Multiple etiologies are associated with increased motion in the cervical spine; some are physiologic or compensatory and others are pathologic. The standard radiographic evaluation of instability and ligamentous injury in the cervical spine consists of lateral flexion and extension x-ray views, but no single pattern of injury is identified in whiplash injuries. Fluoroscopy or cineradiographic techniques may be more sensitive than other methods for evaluating subtle abnormal motion in the cervical spine. The increased motion thus detected then must be evaluated to determine whether it represents normal physiologic motion, normal compensatory motion, motion related to underlying degenerative disk and/or facet disease, or increased motion related to ligamentous injury. Imaging studies should be performed and interpreted as instructed in the AMA Guides.

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