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Extracting extensor digitorum communis activation patterns using high-density surface electromyography.

Hu X, Suresh NL, Xue C, Rymer WZ - Front Physiol (2015)

Bottom Line: Our results revealed distinct activation patterns during individual finger extensions, especially between index and middle finger extensions, although the activation between ring and little finger extensions showed strong covariance.We also found that distinct activation patterns were more discernible in the proximal-distal direction than in the radial-ulnar direction.Such information can also provide a basis for understanding hand impairment in individuals with neural disorders.

View Article: PubMed Central - PubMed

Affiliation: Sensory Motor Performance Program, Single Motor Unit Lab, Rehabilitation Institute of Chicago Chicago, IL, USA.

ABSTRACT
The extensor digitorum communis muscle plays an important role in hand dexterity during object manipulations. This multi-tendinous muscle is believed to be controlled through separate motoneuron pools, thereby forming different compartments that control individual digits. However, due to the complex anatomical variations across individuals and the flexibility of neural control strategies, the spatial activation patterns of the extensor digitorum communis compartments during individual finger extension have not been fully tracked under different task conditions. The objective of this study was to quantify the global spatial activation patterns of the extensor digitorum communis using high-density (7 × 9) surface electromyogram (EMG) recordings. The muscle activation map (based on the root mean square of the EMG) was constructed when subjects performed individual four finger extensions at the metacarpophalangeal joint, at different effort levels and under different finger constraints (static and dynamic). Our results revealed distinct activation patterns during individual finger extensions, especially between index and middle finger extensions, although the activation between ring and little finger extensions showed strong covariance. The activation map was relatively consistent at different muscle contraction levels and for different finger constraint conditions. We also found that distinct activation patterns were more discernible in the proximal-distal direction than in the radial-ulnar direction. The global spatial activation map utilizing surface grid EMG of the extensor digitorum communis muscle provides information for localizing individual compartments of the extensor muscle during finger extensions. This is of potential value for identifying more selective control input for assistive devices. Such information can also provide a basis for understanding hand impairment in individuals with neural disorders.

No MeSH data available.


Related in: MedlinePlus

Exemplar root mean square (RMS) map of individual finger and four-finger extensions. The RMS maps, based on monopolar EMG signals, were shown in relative dimensions. (A) RMS map in the four-finger extension task. (B) RMS maps in individual finger extension tasks. The centroid marks are also shown over the RMS map. Note that the color coding scales individually with each map.
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Figure 3: Exemplar root mean square (RMS) map of individual finger and four-finger extensions. The RMS maps, based on monopolar EMG signals, were shown in relative dimensions. (A) RMS map in the four-finger extension task. (B) RMS maps in individual finger extension tasks. The centroid marks are also shown over the RMS map. Note that the color coding scales individually with each map.

Mentions: The exemplar distributions of muscle activation when different fingers extended in dynamic and high effort conditions are shown in Figure 3. The centroids of the RMS are shown in crossed circles. When the four fingers extended simultaneously (Figure 3A), the entire extensor digitorum communis was active. However, when individual fingers extended separately (Figure 3B), distinct regions of the extensor digitorum were selectively activated, with the index finger in the most distal region, the middle finger in the most proximal region, and the ring and little fingers in between. Such distinct regions of activation allow the detection of anatomical locations of extensor digitorum in controlling individual finger extensions.


Extracting extensor digitorum communis activation patterns using high-density surface electromyography.

Hu X, Suresh NL, Xue C, Rymer WZ - Front Physiol (2015)

Exemplar root mean square (RMS) map of individual finger and four-finger extensions. The RMS maps, based on monopolar EMG signals, were shown in relative dimensions. (A) RMS map in the four-finger extension task. (B) RMS maps in individual finger extension tasks. The centroid marks are also shown over the RMS map. Note that the color coding scales individually with each map.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4593961&req=5

Figure 3: Exemplar root mean square (RMS) map of individual finger and four-finger extensions. The RMS maps, based on monopolar EMG signals, were shown in relative dimensions. (A) RMS map in the four-finger extension task. (B) RMS maps in individual finger extension tasks. The centroid marks are also shown over the RMS map. Note that the color coding scales individually with each map.
Mentions: The exemplar distributions of muscle activation when different fingers extended in dynamic and high effort conditions are shown in Figure 3. The centroids of the RMS are shown in crossed circles. When the four fingers extended simultaneously (Figure 3A), the entire extensor digitorum communis was active. However, when individual fingers extended separately (Figure 3B), distinct regions of the extensor digitorum were selectively activated, with the index finger in the most distal region, the middle finger in the most proximal region, and the ring and little fingers in between. Such distinct regions of activation allow the detection of anatomical locations of extensor digitorum in controlling individual finger extensions.

Bottom Line: Our results revealed distinct activation patterns during individual finger extensions, especially between index and middle finger extensions, although the activation between ring and little finger extensions showed strong covariance.We also found that distinct activation patterns were more discernible in the proximal-distal direction than in the radial-ulnar direction.Such information can also provide a basis for understanding hand impairment in individuals with neural disorders.

View Article: PubMed Central - PubMed

Affiliation: Sensory Motor Performance Program, Single Motor Unit Lab, Rehabilitation Institute of Chicago Chicago, IL, USA.

ABSTRACT
The extensor digitorum communis muscle plays an important role in hand dexterity during object manipulations. This multi-tendinous muscle is believed to be controlled through separate motoneuron pools, thereby forming different compartments that control individual digits. However, due to the complex anatomical variations across individuals and the flexibility of neural control strategies, the spatial activation patterns of the extensor digitorum communis compartments during individual finger extension have not been fully tracked under different task conditions. The objective of this study was to quantify the global spatial activation patterns of the extensor digitorum communis using high-density (7 × 9) surface electromyogram (EMG) recordings. The muscle activation map (based on the root mean square of the EMG) was constructed when subjects performed individual four finger extensions at the metacarpophalangeal joint, at different effort levels and under different finger constraints (static and dynamic). Our results revealed distinct activation patterns during individual finger extensions, especially between index and middle finger extensions, although the activation between ring and little finger extensions showed strong covariance. The activation map was relatively consistent at different muscle contraction levels and for different finger constraint conditions. We also found that distinct activation patterns were more discernible in the proximal-distal direction than in the radial-ulnar direction. The global spatial activation map utilizing surface grid EMG of the extensor digitorum communis muscle provides information for localizing individual compartments of the extensor muscle during finger extensions. This is of potential value for identifying more selective control input for assistive devices. Such information can also provide a basis for understanding hand impairment in individuals with neural disorders.

No MeSH data available.


Related in: MedlinePlus