Movement Path Tortuosity Predicts Compliance With Therapeutic Behavioral Prompts in Patients With Traumatic Brain Injury.

OBJECTIVE: Rehabilitation of patients with traumatic brain injury typically includes therapeutic prompts for keeping appointments and adhering to medication regimens. Level of cognitive impairment may significantly affect a traumatic brain injury victim's ability to benefit from text-based prompting. We tested the hypothesis that spatial disorientation as measured by movement path tortuosity during ambulation would be associated with poorer compliance with automated prompts by veterans actively being treated for traumatic brain injury. SETTING: Clinical polytrauma center. PARTICIPANTS: Ten (1 female) veteran patients mean age = 35.4 (SD = 12.4) years. DESIGN: Small group correlational study without random assignment. MAIN MEASURES: Fractal Dimension, a measure of movement path tortuosity derived from a GPS logging device used to record casual outdoor ambulation at the start of the study. Compliance with smart home machine-generated therapeutic prompts received during rehabilitation at the James A. Haley Veterans Administration Hospital Polytrauma Transitional Rehabilitation Program. A patient was compliant with a prompt if they transited from where the prompt was presented to the prescribed destination (both within the Polytrauma Transitional Rehabilitation Program) within 30 minutes. Noncompliance was failure to appear at the destination within the allotted time. RESULTS: Fractal dimension was significantly inversely related to overall prompt compliance (r = -0.603, n = 10, P = .032; 1-tailed). CONCLUSIONS: The findings support the hypothesis that increased spatial disorientation adversely impacts compliance with automated prompts throughout therapy. The results are consistent with previous studies linking elevated path tortuosity to cognitive impairment and increased risk for falls in assisted living facility residents.

Decreased Movement Path Tortuosity Is Associated With Improved Functional Status in Patients With Traumatic Brain Injury.

OBJECTIVE: To determine if movement path tortuosity in everyday ambulation decreases in Veterans being treated in a residential setting for traumatic brain injury. Elevated path tortuosity is observed in assisted living facility residents with cognitive impairment and at risk for falls, and tortuosity may decrease over the course of cognitive rehabilitation received by the Veterans. If observed, decreased tortuosity may be linked to improved clinical outcomes. DESIGN: Longitudinal observational study without random assignment. SETTING: Veterans Affairs Medical Center inpatient residential polytrauma treatment facility. PATIENTS: Twenty-two Veterans enrolled in a postacute predischarge residential polytrauma treatment facility. INTERVENTIONS: None, observation-only. MAIN OUTCOME MEASURE: Mayo-Portland Adaptability Index-4, and movement path tortuosity measured by Fractal Dimension (Fractal D). Fractal D was obtained continuously from an indoor movement tracking system primarily used to provide machine-generated prompts and reminders to facilitate activities of daily living. Patients were deemed "responders" (N = 10) if a significant linear decline in Fractal D occurred over the course of treatment, or nonresponders (N = 12) if no significant decline was observed. RESULTS: Responders had lower discharge Mayo-Portland Adaptability Inventory scores (mean = 32.6, SD = 9.53) than non-responders (mean = 39.5, SD = 6.02) (F = 2.07, df = 20, P = .05). Responders and nonresponders did not differ on initial injury severity or other demographic measures. CONCLUSIONS: Fractal D, a relatively simple measure of movement path tortuosity can be linked to functional recovery from traumatic brain injury.

Path tortuosity in everyday movements of elderly persons increases fall prediction beyond knowledge of fall history, medication use, and standardized gait and balance assessments.

OBJECTIVES: We hypothesized that variability in voluntary movement paths of assisted living facility (ALF) residents would be greater in the week preceding a fall compared with residents who did not fall. DESIGN: Prospective, observational study using telesurveillance technology. SETTING: Two ALFs. PARTICIPANTS: The sample consisted of 69 older ALF residents (53 female) aged 76.9 (SD ± 11.9 years). MEASUREMENT: Daytime movement in ALF common use areas was automatically tracked using a commercially available ultra-wideband radio real-time location sensor network with a spatial resolution of approximately 20 cm. Movement path variability (tortuosity) was gauged using fractal dimension (fractal D). A logistic regression was performed predicting movement related falls from fractal D, presence of a fall in the prior year, psychoactive medication use, and movement path length. Fallers and non-fallers were also compared on activities of daily living requiring supervision or assistance, performance on standardized static and dynamic balance, and stride velocity assessments gathered at the start of a 1-year fall observation period. Fall risk due to cognitive deficit was assessed by the Mini Mental Status Examination (MMSE), and by clinical dementia diagnoses from participant's activities of daily living health record. RESULTS: Logistic regression analysis revealed odds of falling increased 2.548 (P = .021) for every 0.1 increase in fractal D, and having a fall in the prior year increased odds of falling by 7.36 (P = .006). There was a trend for longer movement paths to reduce the odds of falling (OR .976 P = .08) but it was not significant. Number of psychoactive medications did not contribute significantly to fall prediction in the model. Fallers had more variable stride-to-stride velocities and required more activities of daily living assistance. CONCLUSIONS: High fractal D levels can be detected using commercially available telesurveillance technologies and offers a new tool for health services administrators seeking to reduce falls at their facilities.

Wireless orientation sensors: their suitability to measure head movement for neck pain assessment.

The purpose of this study was to verify the performance and suitability of new generation 3D wireless orientations sensors to measure cervical range of movement against a criterion standard instrument, an electromagnetic motion analysis system (Fastrak-Polhemus). The wireless orientation sensor (InertiaCube 3) consists of 9 motion-sensing elements: 3 accelerometers, 3 angular velocity rate transducers and 3 magnetometers. Measurements of cervical range of motion in each primary plane, left-lateral flexion, flexion and left rotation were directly compared from both systems in 10 normal asymptomatic subjects. Results showed very high cross-correlations (.99-.97) and low average root mean square errors (0.7-2.5 degrees). We conclude that orientation sensors are a valid, accurate and suitable device for obtaining cervical joint ranges of motion in the primary plane of movement.

Gait event detection using linear accelerometers or angular velocity transducers in able-bodied and spinal-cord injured individuals.

We report on three different methods of gait event detection (toe-off and heel strike) using miniature linear accelerometers and angular velocity transducers in comparison to using standard pressure-sensitive foot switches. Detection was performed with normal and spinal-cord injured subjects. The detection of end contact (EC), normally toe-off, and initial contact (IC) normally, heel strike was based on either foot linear accelerations or foot sagittal angular velocity or shank sagittal angular velocity. The results showed that all three methods were as accurate as foot switches in estimating times of IC and EC for normal gait patterns. In spinal-cord injured subjects, shank angular velocity was significantly less accurate (p<0.02). We conclude that detection based on foot linear accelerations or foot angular velocity can correctly identify the timing of IC and EC events in both normal and spinal-cord injured subjects.

The development, validity, and reliability of a manual muscle testing device with integrated limb position sensors.

OBJECTIVE: To report the development and validation of a new hand-held muscle strength-testing device that is integrated with orientation sensors and designed to test the strength of major muscle groups at a given limb or joint position. DESIGN: Design description and validation study. SETTING: University-based human movement facility. PARTICIPANTS: Twenty-eight able-bodied, healthy subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: A device was developed based on a hand-held force dynamometer with integrated orientation sensors. The validity and reliability (interrater, intertrial) of 5 maximum isometric contractions of hip flexion, knee extension, and ankle plantarflexion and dorsiflexion were assessed. The results were compared with those from an isokinetic dynamometer (KinCom). RESULTS: The new manual muscle tester was highly reliable and valid in estimating muscle strength of the lower limbs. The coefficient of variation between trials of all movements was low, with a mean less than 10% (range, 3.7%-8.9%). The only significant difference in muscle strength between the new device and the isokinetic dynamometer was found for hip flexion. CONCLUSIONS: The new hand-held muscle strength tester appears to be a reliable and valid clinical assessment tool that can be used to objectively assess muscle strength at particular limb positions and/or joint angles. This feature appears to represent a technical advance in portable muscle strength devices, providing comparable information to those obtained by isokinetic dynamometers at a fraction of the cost and size. However, the device needs to be validated in clinical populations, such as patients with spinal cord injury and stroke, in order to demonstrate its general clinical utility.