Development and evaluation of a head-controlled human-computer interface with mouse-like functions for physically disabled users

A Low-Power Wearable Stand-Alone Tongue Drive System for People With Severe Disabilities

This paper presents a low-power stand-alone tongue drive system (sTDS) used for individuals with severe disabilities to potentially control their environment such as computer, smartphone, and wheelchair using their voluntary tongue movements. A low-power local processor is proposed, which can perform signal processing to convert raw magnetic sensor signals to user-defined commands, on the sTDS wearable headset, rather than sending all raw data out to a PC or smartphone. The proposed sTDS significantly reduces the transmitter power consumption and subsequently increases the battery life. Assuming the sTDS user issues one command every 20 ms, the proposed local processor reduces the data volume that needs to be wirelessly transmitted by a factor of 64, from 9.6 to 0.15 kb/s. The proposed processor consists of three main blocks: serial peripheral interface bus for receiving raw data from magnetic sensors, external magnetic interference attenuation to attenuate external magnetic field from the raw magnetic signal, and a machine learning classifier for command detection. A proof-of-concept prototype sTDS has been implemented with a low-power IGLOO-nano field programmable gate array (FPGA), bluetooth low energy, battery and magnetic sensors on a headset, and tested. At clock frequency of 20 MHz, the processor takes 6.6 s and consumes 27 nJ for detecting a command with a detection accuracy of 96.9%. To further reduce power consumption, an application-specified integrated circuit processor for the sTDS is implemented at the postlayout level in 65-nm CMOS technology with 1-V power supply, and it consumes 0.43 mW, which is 10 lower than FPGA power consumption and occupies an area of only 0.016 mm.

Head Rotation Movement Times

OBJECTIVE

The aim of this study was to measure head rotation movement times in a Fitts' paradigm and to investigate the transition region from ballistic movements to visually controlled movements as the task index of difficulty (ID) increases.

BACKGROUND

For head rotation, there are gaps in the knowledge of the effects of movement amplitude and task difficulty around the critical transition region from ballistic movements to visually controlled movements.

METHOD

Under the conditions of 11 ID values (from 1.0 to 6.0) and five movement amplitudes (20° to 60°), participants performed a head rotation task, and movement times were measured.

RESULTS

Both the movement amplitude and task difficulty have effects on movement times at low IDs, but movement times are dependent only on ID at higher ID values. Movement times of participants are higher than for arm/hand movements, for both ballistic and visually controlled movements. The information-processing rate of head rotational movements, at high ID values, is about half that of arm movements.

CONCLUSION

As an input mode, head rotations are not as efficient as the arm system either in ability to use rapid ballistic movements or in the rate at which information may be processed.

APPLICATION

The data of this study add to those in the review of Hoffmann for the critical IDs of different body motions. The data also allow design for the best arrangement of display that is under the design constraints of limited display area and difficulty of head-controlled movements in a data-inputting task.

Comparison of the using ability between a smartphone and a conventional mobile phone in people with cervical cord injury

OBJECTIVE

To investigate the ability of spinal cord injury (SCI) patients in the use mobile cellular devices, especially the smartphone.

METHODS

Seventeen people with motor complete cervical SCI participated in the study. The assist-devices deemed most fitting were introduced to the patients: a mouth stick, multifunctional splint, activities of daily living (ADL) splint, universal cuff or none of the above. To determine the effective devices, a Multi-Directional Click Test (MDCT), Phone Number Test (PNT), and individual satisfaction inquiry were used. The most appropriate assist device was selected by MDCT. Subsequently PNT and individual satisfaction inquiry were performed with the conventional model and compared.

RESULTS

Those with C4 cord injury chose mouth stick. Those with C5 cord injury chose multifunctional splint (3 people) and ADL splint (2 people). Those with C6 cord injury chose universal cuff (3 people) or bare hands only. Those with C7 cord injury chose universal cuff (3 people). With a smartphone, all participants were able to complete the PNT. With a conventional model, only twelve participants (71%) were able to complete the same test. While it took 26.8±6.8 seconds with a conventional model to complete PNT, the same test took 18.8±10.9 seconds to complete with a smartphone (p<0.05). Overall, participants expressed higher satisfaction when using a smartphone.

CONCLUSION

The results offer a practical insight into the appropriate assist devices for SCI patients who wish to use mobile cellular devices, particularly smartphones. When the SCI patients are given the use of a smartphone with the appropriate assist devices, the SCI patients are expected to access mobile cellular device faster and with more satisfaction.

A dual-mode human computer interface combining speech and tongue motion for people with severe disabilities

We are presenting a new wireless and wearable human computer interface called the dual-mode Tongue Drive System (dTDS), which is designed to allow people with severe disabilities to use computers more effectively with increased speed, flexibility, usability, and independence through their tongue motion and speech. The dTDS detects users' tongue motion using a magnetic tracer and an array of magnetic sensors embedded in a compact and ergonomic wireless headset. It also captures the users' voice wirelessly using a small microphone embedded in the same headset. Preliminary evaluation results based on 14 able-bodied subjects and three individuals with high level spinal cord injuries at level C3-C5 indicated that the dTDS headset, combined with a commercially available speech recognition (SR) software, can provide end users with significantly higher performance than either unimodal forms based on the tongue motion or speech alone, particularly in completing tasks that require both pointing and text entry.

Activity, severity and impact of respiratory disease in primary antibody deficiency syndromes

PURPOSE

Some patients with primary antibody deficiency (PAD) syndromes develop bronchiectasis. In immunocompetent patients with bronchiectasis, key clinico-pathophysiological relationships exist between exacerbation frequency, lung function, health-status, infection and inflammation. It is not known whether such relationships are present in PAD. It is also not known how local and systemic inflammation in PAD compares with that in immunocompetent (non-PAD) bronchiectasis patients.

METHOD

We assessed symptoms, exacerbation frequency, health-status, lung function, CT, airway and systemic inflammation and infection in 33 PAD patients and 20 immunocompetent controls with bronchiectasis.

RESULTS

Despite less severe airflow obstruction, PAD patients had similar health-status impairment and greater airway (sputum log10 IL-6 2.71 vs. 1.81 pg/ml, p = 0.001) and greater systemic inflammation than immunocompetent bronchiectasis controls (serum log10 CRP 0.77 vs. 0.36 mg/l, p = 0.001). In PAD, cross-sectional markers of disease severity (CT and lung function) did not relate to inflammatory markers of disease activity, however there was a relationship between FEV1 decline rate and systemic inflammation (IL-6; r = 0.42, p = 0.036) and the magnitude of the systemic inflammatory response was related to that in the airway. Correlation between generic SF36 and respiratory SGRQ questionnaires (r = -0.79, p < 0.001) suggests that much health-status impairment in PAD relates to respiratory involvement. Health-status was associated with dyspnoea (rho = 0.77, p < 0.001), respiratory infection frequency (rho = 0.48, p = 0.016), lung function (FEV1: r = -0.60, p = 0.001) and rate of lung function decline (r = 0.41, p = 0.047).

CONCLUSION

The major findings of this analysis are that in patients with PAD, cross-sectional markers of disease severity such as lung function and CT extent of disease do not reflect disease activity as assessed by airway and systemic inflammation. In addition, there is a relationship between the rate of progression of lung disease and the severity of the systemic inflammatory response which itself is related to that in the airway. Much of the quality of life impact in PAD relates to respiratory involvement, specifically the severity of airflow obstruction, respiratory exacerbation frequency and dyspnoea. Finally, patients with PAD had greater airway and systemic inflammation than a control population with non-PAD bronchiectasis which may suggest a dysregulated airway immune response.

A novel five degree of freedom user command controller in people with spinal cord injury and non-injured for full upper extremity neuroprostheses, wearable powered orthoses and prosthetics

An independent lifestyle requires the ability to place the hand in the complete workspace in concert with hand grasp and release. A novel user command controller monitoring head position for purpose of controlling hand location and orientation is proposed and demonstrated. The controller detected five degrees of freedom which were applied to upper limb movements including forearm and hand placement in three-dimensional space. The controller was evaluated by having subjects complete tracking tasks manipulating a simulated on-screen upper limb representation. Thirteen of the eighteen subjects assessed using the controller had sustained a spinal cord injury at or above the sixth cervical vertebra. Two of the injured subjects with decreased cervical spine mobility were unable to operate the controller. The remaining subjects performed the tracking tasks effectively after minimal training. This simple five-degree of freedom controller has been proposed for the use by those disabled by upper limb amputation, paralysis, weakness or hypertonicity.

Evaluation of vision-based head-trackers for assistive devices

This paper presents a new evaluation methodology for assistive devices employing head-tracking systems based on an adaptation of the Fitts Test. This methodology is used to compare the effectiveness and performance of a new vision-based head tracking system using face, skin and motion detection techniques with two existing head tracking devices and a standard mouse. The application context and the abilities of the user are combined with the results from the modified Fitts Test to help determine the most appropriate devices for the user. The results suggest that this modified form of the Fitts test can be effectively employed for the comparison of different access technologies.

Microswitch and keyboard-emulator technology to facilitate the writing performance of persons with extensive motor disabilities

This study assessed the effectiveness of microswitches for simple responses (i.e., partial hand closure, vocalization, and hand stroking) and a keyboard emulator to facilitate the writing performance of three participants with extensive motor disabilities. The study was carried out according to an ABAB design. During the A phases, the participants (one child and two adults) were to write using the responses and technology available to them prior to this study. During the B phases, they used the new responses and technology. Data showed that two of the three participants had a faster writing performance during the B phases while the third participant had a slower writing performance. All three participants indicated a clear preference for the use of the new responses and technology, which were considered relatively easy and comfortable to manage and did not seem to cause any specific signs of tiredness. Implications of the findings are discussed.