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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.

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Identification rate (mean ± standard deviation, n = 10) for pulse number. The error bars show the identification rates for five individual pulse numbers. ** indicates a significant difference (p < 0.01). * indicates a significant difference (p < 0.05).
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Figure 6: Identification rate (mean ± standard deviation, n = 10) for pulse number. The error bars show the identification rates for five individual pulse numbers. ** indicates a significant difference (p < 0.01). * indicates a significant difference (p < 0.05).

Mentions: The overall identification rate for the five pulse numbers (1, 4, 8, 12, 20) was 90.8 ± 6.0%. However, the subjects’ capability differed in identification of the five pulse numbers (as shown in Figure 6). Identification rate for one pulse was 100% with all 10 subjects, while identification of 12 pulses appeared most challenging (82.0 ± 16.2%). The results of repeated measures ANOVA test showed a significant difference in the performance of identifying the five pulse numbers (p < 0.01). Multiple comparisons indicated significant difference between the following pulse number pairs: 1 and 8 (p < 0.01), 1 and 12 (p < 0.01), 4 and 12 (p < 0.05), 12 and 20 (p < 0.01). Table 3 lists in details the percentages of reported or decoded hand opening level and the pulse number actually delivered.


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

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

Identification rate (mean ± standard deviation, n = 10) for pulse number. The error bars show the identification rates for five individual pulse numbers. ** indicates a significant difference (p < 0.01). * indicates a significant difference (p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 6: Identification rate (mean ± standard deviation, n = 10) for pulse number. The error bars show the identification rates for five individual pulse numbers. ** indicates a significant difference (p < 0.01). * indicates a significant difference (p < 0.05).
Mentions: The overall identification rate for the five pulse numbers (1, 4, 8, 12, 20) was 90.8 ± 6.0%. However, the subjects’ capability differed in identification of the five pulse numbers (as shown in Figure 6). Identification rate for one pulse was 100% with all 10 subjects, while identification of 12 pulses appeared most challenging (82.0 ± 16.2%). The results of repeated measures ANOVA test showed a significant difference in the performance of identifying the five pulse numbers (p < 0.01). Multiple comparisons indicated significant difference between the following pulse number pairs: 1 and 8 (p < 0.01), 1 and 12 (p < 0.01), 4 and 12 (p < 0.05), 12 and 20 (p < 0.01). Table 3 lists in details the percentages of reported or decoded hand opening level and the pulse number actually delivered.

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