Biomedical subjects

Anthony L Ricamato

Publications and source records attributed to Anthony L Ricamato.

3 recordsLinked to original sources

PubMed2004

Quantification of the dynamic properties of EMG patterns during gait.

A technique for analyzing and comparing the dynamic properties of electromyographic (EMG) patterns collected during gait is presented. A gait metric is computed, consisting of both magnitude (amplitude) and phase (timing) components. For the magnitude component, the processed EMG pattern is compared to a normative EMG pattern obtained under similar walking conditions, where the metric is incremented if the muscle is firing during expected active regions or is silent during expected inactive regions. The magnitude metric is penalized when the EMG is silent during phases of expected activity or when the EMG is active in regions of expected inactivity. The phase component of the metric computes the percentage of the gait cycle when the muscle is firing appropriately, that is, active in expected active regions and silent in expected inactive regions. The magnitude and phase components of the metric are normalized and combined to yield the EMG pattern that demonstrates the closest characteristics compared to normative gait data collected under similar walking conditions. Using experimental data, the proposed gait metric was tested and accurately reflects the observed changes in the EMG patterns. Clinical uses for the gait metric are discussed in relation to gait therapies, such as determining optimal gait training conditions in individuals following stroke and spinal cord injury.

Diagnosis, Computer-Assisted↗

PubMedDate not supplied

Estimation of active cortical current source regions using a vector representation scanning approach.

The objective of this article is to present a framework for cortical current source reconstruction that extracts a center and magnitude of electrical brain activity from EEG signals. High-resolution EEG recordings, a subject-specific MRI-based electromagnetic boundary element method (BEM) model, and a channel reduction technique are used. This new geometric measure combines the magnitude and spatial location of electrical brain activity of each of the identified subsets of channels into a three-dimensional resultant vector. The combination of the two approaches constitutes a source reconstruction scanning technique that provides a real-time estimation of cortical centers that can be tracked over time. Simulations demonstrate that the ability of this method to find the best-fit cortical location is more robust both in terms of accuracy and precision than traditional approaches for single-source conditions. Experimental validation demonstrates its ability to localize and separate cortical activity in plausible sites for two different motor tasks. Finally, this method provides a statistical measure to compare electrical brain activity associated with different motor tasks.

Adult↗

PubMedDate not supplied

Electrical cortical activity associated with joint torque direction in the human arm.

The objective of this study is to determine whether electrical brain activity differs for static joint torques generated in the elbow flexion/extension and shoulder abduction/adduction directions in humans. Electrical brain activity was quantified using a technique that incorporates a realistic, subject-specific electromagnetic head model to create a three-dimensional spatial resultant vector representation of the cortical region of activation. The findings demonstrate that generation of torque in each of the four directions produced significantly different locations of centers of cortical activation. These differences in location were maintained from preparatory to the early execution phases of the task. The organization of the centers of cortical activity during the generation of elbow/shoulder torques resulted in centers associated with the generation of elbow torques that were more lateral than centers accompanying shoulder torques in all five subjects tested. The authors conclude that electrical brain activity is spatially organized during the generation of joint torques in opposing directions at the elbow and shoulder joints. In addition, the results indicate that the center of the electrical brain activity associated with these static tasks is localized over the primary motor cortex as opposed to secondary sensorimotor cortices.

Adult↗