Gait Assessment Using Three-Dimensional Acceleration of the Trunk in Idiopathic Normal Pressure Hydrocephalus

Background: The subjective evaluation of pathological gait exhibits a low inter-rater reliability. Therefore, we developed a three-dimensional acceleration of the trunk during walking to assess the pathological gait quantitatively.Methods: We evaluated 97 patients who underwent the cerebrospinal tap test and were diagnosed with idiopathic normal pressure hydrocephalus (iNPH) and 68 healthy elderlies. The gait features of all patients were evaluated and classified as one of the following: freezing of gait, wide-based gait, short-stepped gait, shuffling gait, instability, gait festination, difficulty in changing direction, and balance disorder in standing up. All gait features of 68 healthy elderlies were treated as normal. Trunk acceleration was recorded automatically by a smartphone placed on the umbilicus during a 15-foot walking test. Two novel indices were created. The first index was a trunk acceleration index, which was defined as (forward acceleration fluctuation) + (vertical acceleration fluctuation) – (lateral acceleration fluctuation) based on the multivariate logistics regression model, and the second index was created by multiplying the forward acceleration with the vertical acceleration. Additionally, 95% confidence ellipsoid volume of the three-dimensional accelerations was assessed.Results: Forward and vertical acceleration fluctuations were significantly associated with the probability of an iNPH-specific pathological gait. The trunk acceleration index demonstrated the strongest association with the probability of an iNPH-specific pathological gait. The areas under the receiver-operating characteristic curves for detecting 100% probability of an iNPH-specific pathological gait were 86.9% for forward acceleration fluctuation, 88.0% for vertical acceleration fluctuation, 82.8% for lateral acceleration fluctuation, 89.0% for trunk acceleration index, 88.8% for forward × vertical acceleration fluctuation, and 87.8% for 95% confidence ellipsoid volume of the three-dimensional accelerations.Conclusions: The probability of a pathological gait specific to iNPH is high at the trunk acceleration fluctuation, reduced in the forward and vertical directions, and increased in the lateral direction.

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Changes in Cerebral Blood Flow during Cerebrospinal Fluid Pressure Manipulation in Patients with Normal Pressure Hydrocephalus: A Methodological Study

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/00004647-200405000-00012 ◽

2004 ◽

Vol 24 (5) ◽

pp. 579-587 ◽

Cited By ~ 47

Author(s):

Brian K. Owler ◽

Alonso Pena ◽

Shahan Momjian ◽

Zofia Czosnyka ◽

Marek Czosnyka ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Normal Pressure Hydrocephalus ◽

Fluid Pressure ◽

Three Dimensional ◽

Normal Pressure ◽

Element Analysis ◽

Csf Pressure ◽

Arterial Blood ◽

Positron Emission

The combination of cerebral blood flow measurement using 15O-water positron emission tomography with magnetic resonance coregistration and CSF infusion studies was used to study the global and regional changes in CBF with changes in CSF pressure in 15 patients with normal pressure hydrocephalus. With increases in CSF pressure, there was a variable increase in arterial blood pressure between individuals and global CBF was reduced, including in the cerebellum. Regionally, mean CBF decreased in the thalamus and basal ganglia, as well as in white matter regions. These reductions in CBF were significantly correlated with changes in the CSF pressure and with proximity to the ventricles. A three-dimensional finite-element analysis was used to analyze the effects on ventricular size and the distribution of stress during infusion. To study regional cerebral autoregulation in patients with possible normal pressure hydrocephalus, a sensitive CBF technique is required that provides absolute, not relative normalized, values for regional CBF and an adequate change in cerebral perfusion pressure must be provoked.

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Volume of confidence ellipsoid: a technique for quantifying trunk sway during stance

Biomedical Engineering / Biomedizinische Technik ◽

10.1515/bmt-2014-0012 ◽

2015 ◽

Vol 60 (2) ◽

Cited By ~ 5

Author(s):

Patrik Kutilek ◽

Ondrej Cakrt ◽

Vladimir Socha ◽

Karel Hana

Keyword(s):

Healthy Subjects ◽

Three Dimensional ◽

Principal Component ◽

Eyes Closed ◽

Trunk Sway ◽

Eyes Open ◽

Ellipsoid Volume ◽

Three Degree Of Freedom ◽

Balance Problems ◽

Confidence Ellipsoid

AbstractThe position of the trunk can be negatively affected by many diseases. This work focuses on a noninvasive method of quantifying human postural stability and identifying defects in balance and coordination as a result of the nervous system pathology. We used a three-degree-of-freedom orientation tracker (Xsens MTx unit) placed on a patient’s trunk and measured three-dimensional (3-D) data (pitch, roll, and yaw) during quiet stance. The principal component analysis was used to analyze the data and to determine the volume of 3-D 95% confidence ellipsoid. Using this method, we were able to model the distribution of the measured 3-D data (pitch, roll, and yaw). Eight patients with degenerative cerebellar disease and eight healthy subjects in this study were measured during stance, with eyes open and eyes closed, and statistical analysis was performed. The results of the new method based on the 3-D confidence ellipsoid show that the volumes related to the patients are significantly larger than the volumes related to the healthy subjects. The concept of confidence ellipsoid volume, although known to the biomechanics community, has not been used before to study the postural balance problems. The method can also be used to study, for example, head and pelvis movements or alignments during stance.

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