Online transcranial Doppler ultrasonographic control of an onscreen keyboard
Brain-computer interface (BCI) systems exploit brain activity for generating a control command and may be used by individuals with severe motor disabilities as an alternative means of communication. An emerging brain monitoring modality for BCI development is transcranial Doppler ultrasonography (TC...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2014-04-01
|
| Series: | Frontiers in Human Neuroscience |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00199/full |
| _version_ | 1818850738113085440 |
|---|---|
| author | Jie eLu Jie eLu Khondaker Abdullah Al Mamun Khondaker Abdullah Al Mamun Tom eChau Tom eChau |
| author_facet | Jie eLu Jie eLu Khondaker Abdullah Al Mamun Khondaker Abdullah Al Mamun Tom eChau Tom eChau |
| author_sort | Jie eLu |
| collection | DOAJ |
| description | Brain-computer interface (BCI) systems exploit brain activity for generating a control command and may be used by individuals with severe motor disabilities as an alternative means of communication. An emerging brain monitoring modality for BCI development is transcranial Doppler ultrasonography (TCD), which facilitates the tracking of cerebral blood flow velocities associated with mental tasks. However, TCD-BCI studies to date have exclusively been offline. The feasibility of a TCD-based BCI system hinges on its online performance. In this paper, an online TCD-BCI system was implemented, bilaterally tracking blood flow velocities in the middle cerebral arteries for system-paced control of a scanning keyboard. Target letters or words were selected by repetitively rehearsing the spelling while imagining the writing of the intended word, a left-lateralized task. Undesired letters or words were bypassed by performing visual tracking, a non-lateralized task. The keyboard scanning period was 15s. With 10 able-bodied right-handed young adults, the two mental tasks were differentiated online using a Naïve Bayes classification algorithm and a set of time-domain, user-dependent features. The system achieved an average specificity and sensitivity of 81.44 ± 8.35% and 82.30 ± 7.39%, respectively. The level of agreement between the intended and machine-predicted selections was moderate (=0.60). The average information transfer rate was 0.87 bits/min with an average throughput of 0.31 ± 0.12 character/min. These findings suggest that an online TCD-BCI can achieve reasonable accuracies with an intuitive language task, but with modest throughput. Future interface and signal classification enhancements are required to improve communication rate. |
| first_indexed | 2024-12-19T06:53:54Z |
| format | Article |
| id | doaj.art-a2a117e2e3fa4494a3c64ee00fc90e2c |
| institution | Directory Open Access Journal |
| issn | 1662-5161 |
| language | English |
| last_indexed | 2024-12-19T06:53:54Z |
| publishDate | 2014-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj.art-a2a117e2e3fa4494a3c64ee00fc90e2c2022-12-21T20:31:37ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612014-04-01810.3389/fnhum.2014.0019958450Online transcranial Doppler ultrasonographic control of an onscreen keyboardJie eLu0Jie eLu1Khondaker Abdullah Al Mamun2Khondaker Abdullah Al Mamun3Tom eChau4Tom eChau5Holland Bloorview Kids Rehabilitation HospitalUniversity of TorontoHolland Bloorview Kids Rehabilitation HospitalUniversity of TorontoUniversity of TorontoHolland Bloorview Kids Rehabilitation HospitalBrain-computer interface (BCI) systems exploit brain activity for generating a control command and may be used by individuals with severe motor disabilities as an alternative means of communication. An emerging brain monitoring modality for BCI development is transcranial Doppler ultrasonography (TCD), which facilitates the tracking of cerebral blood flow velocities associated with mental tasks. However, TCD-BCI studies to date have exclusively been offline. The feasibility of a TCD-based BCI system hinges on its online performance. In this paper, an online TCD-BCI system was implemented, bilaterally tracking blood flow velocities in the middle cerebral arteries for system-paced control of a scanning keyboard. Target letters or words were selected by repetitively rehearsing the spelling while imagining the writing of the intended word, a left-lateralized task. Undesired letters or words were bypassed by performing visual tracking, a non-lateralized task. The keyboard scanning period was 15s. With 10 able-bodied right-handed young adults, the two mental tasks were differentiated online using a Naïve Bayes classification algorithm and a set of time-domain, user-dependent features. The system achieved an average specificity and sensitivity of 81.44 ± 8.35% and 82.30 ± 7.39%, respectively. The level of agreement between the intended and machine-predicted selections was moderate (=0.60). The average information transfer rate was 0.87 bits/min with an average throughput of 0.31 ± 0.12 character/min. These findings suggest that an online TCD-BCI can achieve reasonable accuracies with an intuitive language task, but with modest throughput. Future interface and signal classification enhancements are required to improve communication rate.http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00199/fullCommunicationMiddle Cerebral ArterylateralizationBCIhemodynamic responseTCD |
| spellingShingle | Jie eLu Jie eLu Khondaker Abdullah Al Mamun Khondaker Abdullah Al Mamun Tom eChau Tom eChau Online transcranial Doppler ultrasonographic control of an onscreen keyboard Frontiers in Human Neuroscience Communication Middle Cerebral Artery lateralization BCI hemodynamic response TCD |
| title | Online transcranial Doppler ultrasonographic control of an onscreen keyboard |
| title_full | Online transcranial Doppler ultrasonographic control of an onscreen keyboard |
| title_fullStr | Online transcranial Doppler ultrasonographic control of an onscreen keyboard |
| title_full_unstemmed | Online transcranial Doppler ultrasonographic control of an onscreen keyboard |
| title_short | Online transcranial Doppler ultrasonographic control of an onscreen keyboard |
| title_sort | online transcranial doppler ultrasonographic control of an onscreen keyboard |
| topic | Communication Middle Cerebral Artery lateralization BCI hemodynamic response TCD |
| url | http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00199/full |
| work_keys_str_mv | AT jieelu onlinetranscranialdopplerultrasonographiccontrolofanonscreenkeyboard AT jieelu onlinetranscranialdopplerultrasonographiccontrolofanonscreenkeyboard AT khondakerabdullahalmamun onlinetranscranialdopplerultrasonographiccontrolofanonscreenkeyboard AT khondakerabdullahalmamun onlinetranscranialdopplerultrasonographiccontrolofanonscreenkeyboard AT tomechau onlinetranscranialdopplerultrasonographiccontrolofanonscreenkeyboard AT tomechau onlinetranscranialdopplerultrasonographiccontrolofanonscreenkeyboard |