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Human ability in identification of location and pulse number for electrocutaneous stimulation applied on the forearm.

Geng B, Jensen W - J Neuroeng Rehabil (2014)

Bottom Line: The study consisted of three experiments.The performance degraded when both parameters had to be identified likely due to increased cognitive load resulting from multiple tasks.Utilizing the proposed coding strategy in practical prosthetic hands remains to be investigated for clinical evaluation of its feasibility.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Health Science and Technology, Aalborg University, Fredrik Bajers vej 7D, Aalborg, Denmark. bogeng@hst.aau.dk.

ABSTRACT

Background: The need of a sensory feedback system that would improve users' acceptance in prostheses is generally recognized. Feedback of hand opening and position are among the most important concerns of prosthetic users. To address the two concerns, this study investigated the human capability to identify pulse number and location when electrical stimulation applied on the forearm skin. The pulse number may potentially be used to encode the opening of prosthetic hands and stimulation location to encode finger position.

Methods: Ten able-bodied subjects participated in the study. Three electrodes were placed transversely across the ventral forearm spatially encoding three fingers (i.e., thumb, index, and middle finger). Five different pulse numbers (1, 4, 8, 12, and 20) encoded five levels of hand opening. The study consisted of three experiments. In the three experiments, each after a training session, the subjects were required to identify among: (a) five stimulation locations, (b) five pulse numbers, or (c) ten paired combinations of location and pulse number, respectively. The subjects' performance in the three identification tasks was evaluated.

Results: The main results included: 1) the overall identification rate for stimulation location was 92.2 ± 6.2%, while the success rate in two-site stimulation was lower than one-site stimulation; 2) the overall identification rate for pulse number was 90.8 ± 6.0%, and the subjects showed different performance in identification of the five pulse numbers; 3) the overall identification rate decreased to 80.2 ± 11.7% when the subjects were identifying paired parameters.

Conclusions: The results indicated that the spatial (location) and temporal (pulse number) identification performance are promising in electrocutaneous stimulation on the forearm. The performance degraded when both parameters had to be identified likely due to increased cognitive load resulting from multiple tasks. Utilizing the proposed coding strategy in practical prosthetic hands remains to be investigated for clinical evaluation of its feasibility.

Show MeSH
Electrode placement. Three self-adhesive solid gel surface electrodes (D1, D2, D3) were transversely placed 5 cm distant from the elbow crease on the ventral side of the left forearm. The three electrode sites were intended to encode the position of three fingers.
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Figure 1: Electrode placement. Three self-adhesive solid gel surface electrodes (D1, D2, D3) were transversely placed 5 cm distant from the elbow crease on the ventral side of the left forearm. The three electrode sites were intended to encode the position of three fingers.

Mentions: Three self-adhesive solid gel surface electrodes (Ambu Neuroline 700, skin contact size 20 mm × 15 mm, ‘duck foot’ shape, silver/silver chloride) were placed 5 cm distally to the elbow crease on the ventral aspect of the left forearm (Figure 1). A return electrode (PALS Platinum: 40 mm × 64 mm, oval shape) was positioned over the dorsal side of the wrist on the same forearm. The center-to-center distance between the electrodes ranged from 40 mm to 50 mm depending on the size of individual forearms. The skin was prepared by gently shaving when needed and moisturizing with a water-soaked cotton cloth to facilitate electrical conductivity.


Human ability in identification of location and pulse number for electrocutaneous stimulation applied on the forearm.

Geng B, Jensen W - J Neuroeng Rehabil (2014)

Electrode placement. Three self-adhesive solid gel surface electrodes (D1, D2, D3) were transversely placed 5 cm distant from the elbow crease on the ventral side of the left forearm. The three electrode sites were intended to encode the position of three fingers.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4060858&req=5

Figure 1: Electrode placement. Three self-adhesive solid gel surface electrodes (D1, D2, D3) were transversely placed 5 cm distant from the elbow crease on the ventral side of the left forearm. The three electrode sites were intended to encode the position of three fingers.
Mentions: Three self-adhesive solid gel surface electrodes (Ambu Neuroline 700, skin contact size 20 mm × 15 mm, ‘duck foot’ shape, silver/silver chloride) were placed 5 cm distally to the elbow crease on the ventral aspect of the left forearm (Figure 1). A return electrode (PALS Platinum: 40 mm × 64 mm, oval shape) was positioned over the dorsal side of the wrist on the same forearm. The center-to-center distance between the electrodes ranged from 40 mm to 50 mm depending on the size of individual forearms. The skin was prepared by gently shaving when needed and moisturizing with a water-soaked cotton cloth to facilitate electrical conductivity.

Bottom Line: The study consisted of three experiments.The performance degraded when both parameters had to be identified likely due to increased cognitive load resulting from multiple tasks.Utilizing the proposed coding strategy in practical prosthetic hands remains to be investigated for clinical evaluation of its feasibility.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Health Science and Technology, Aalborg University, Fredrik Bajers vej 7D, Aalborg, Denmark. bogeng@hst.aau.dk.

ABSTRACT

Background: The need of a sensory feedback system that would improve users' acceptance in prostheses is generally recognized. Feedback of hand opening and position are among the most important concerns of prosthetic users. To address the two concerns, this study investigated the human capability to identify pulse number and location when electrical stimulation applied on the forearm skin. The pulse number may potentially be used to encode the opening of prosthetic hands and stimulation location to encode finger position.

Methods: Ten able-bodied subjects participated in the study. Three electrodes were placed transversely across the ventral forearm spatially encoding three fingers (i.e., thumb, index, and middle finger). Five different pulse numbers (1, 4, 8, 12, and 20) encoded five levels of hand opening. The study consisted of three experiments. In the three experiments, each after a training session, the subjects were required to identify among: (a) five stimulation locations, (b) five pulse numbers, or (c) ten paired combinations of location and pulse number, respectively. The subjects' performance in the three identification tasks was evaluated.

Results: The main results included: 1) the overall identification rate for stimulation location was 92.2 ± 6.2%, while the success rate in two-site stimulation was lower than one-site stimulation; 2) the overall identification rate for pulse number was 90.8 ± 6.0%, and the subjects showed different performance in identification of the five pulse numbers; 3) the overall identification rate decreased to 80.2 ± 11.7% when the subjects were identifying paired parameters.

Conclusions: The results indicated that the spatial (location) and temporal (pulse number) identification performance are promising in electrocutaneous stimulation on the forearm. The performance degraded when both parameters had to be identified likely due to increased cognitive load resulting from multiple tasks. Utilizing the proposed coding strategy in practical prosthetic hands remains to be investigated for clinical evaluation of its feasibility.

Show MeSH