Assistive robotic arm shown to help boost independence of those with ALS in evaluation study

A recent study has demonstrated that assistive robotic manipulators can help people with amyotrophic lateral sclerosis (ALS) to remain independent.

The study, ‘Assistive Robots for Patients with Amyotrophic Lateral Sclerosis: Exploratory Task-Based Evaluation Study with an Early-Stage Demonstrator’, is published in the journal JMIR Rehabilitation and Assistive Technologies.

Below AT Today has detailed some of the key findings of this assistive technology study.

Background

An assistive robotic manipulator is a supportive device used to control objects or materials without direct physical contact by the operator. This assistive device can be particularly helpful for disabled people who may struggle or be unable to carry out physical tasks.

The study explores whether assistive robotic manipulators can help people with chronic and progressive motor neurone disease ALS to be more independent.

People with ALS experience progressive loss of voluntary motor function, leading up to complete paralysis. The continuous loss of motor function means that those with ALS can struggle to carry out day-to-day tasks like eating, washing, and walking, leading to high dependence and need for support in those affected.

According to the report, assistive technologies can increase the autonomy of people with ALS by supporting with tasks like drinking, preparing food, or personal hygiene. Thus, the use of assistive robotic manipulators is expected to have great potential in promoting independence and motor self-determination among people with functional limitations.

The assistive robotic device and study goals

Robot-assisted services for individual and resource-oriented intensive and palliative care of people with ALS (ROBINA) is a research and development project funded by the German Federal Ministry of Education and Research.

The aim of the project was to develop a semiautomatic robotic manipulator that can be controlled via a multimodal user interface (UI) to support people with ALS in their independence in various daily living activities. Another objective was to ease the pressure off professionals and caregivers from repetitive support activities.

The objective of the study was to identify the specific needs, preferences, and requirements of people with ALS for the development of a semiautonomous robotic manipulator to promote independence in activities of daily living.

Methodology

A total of 11 participants with ALS aged 18 and above took part in the study.

As part of the study, the assistive robotic device incorporated torque sensors in its joints that enabled it to interact sensitively with the participants. It was equipped with a two-fingered gripper. The functional modes of the gripper included opening and closing of the two fingers.

Additionally, the system facilitated real-time bidirectional communication.

The software for control via the patient’s sensors ran on a tablet with Windows operating system. It was implemented as a locally communicating application for modern internet browsers and accessed via control units by the patients. These control units comprised a variety of input devices to best cover each participant’s capabilities, such as joysticks that were directly operated in the hand or attached to a gooseneck mount, a head control system, and an eye control system.

All inputs were mapped to a mouse pointer, with which the patients navigated the menus of the graphical user input (GUI) and controlled the robot. Different task scenarios were implemented as movement sequences that the participants could execute, pause, reset, and customise to their needs.

Evaluation tasks

To determine how well the robotic system worked for users with ALS, the device was given different tasks to carry out to assess its usefulness in helping people be more independent. The system was given four different tasks.

The first task was to “serve a drink” with a silicone straw. This involves the robot gripping a cup and moving the cup to the user’s mouth by using visual mouth tracking. To drink, the participant had to actively move their head towards the straw,

The second task was to “hand over a mobile phone”. Here, the robot picks up and places the mobile phone autonomously in a predefined transfer zone. The phone is in a predefined pickup area. It tracks the phone via visual object recognition.

The third task was “skin scratching”. In this task, the participant selects the duration and intensity of scratching and the type of brush. The robot arm picks up the brush and then slowly approaches the user’s forearm. The participant’s forearm rests on an arm padding, which serves the robot system as position recognition.

Robot sensors continuously check the contact between the brush and the human arm to adjust the robot movement in case of limb position changes. If contact is interrupted, time limit is exceeded, or execution is stopped by the user, the robot stops scratching, places the brush back on the table, and returns to its standby position.

The final task was “free manipulation”. In this scenario, the participant can move the robot arm freely in a defined area and manipulate objects. For a standardised assessment of the task, the participants were asked to stack cubes on top of each other. The participant controlled all movements of the robot systems by clicking six direction levels (left, right, up, down, backward, and forward) and opening and closing the gripper on the UI.

To evaluate these tasks, participants were asked to provide feedback during the tasks (including their facial expressions) as well as complete a questionnaire after each task.

Study results

1. Serve a drink

Of the 11 study participants, nine found that the “serve a drink” scenario for daily life was either very or rather relevant. Only one person found this scenario to be irrelevant for everyday life.

All participants rated the ease of use of the control unit as very easy or rather easy.

The movement speed of the robot was rated as appropriate by 45 percent of the participants. In contrast, 45 percent of the participants rated it as rather slow or very slow. One participant perceived the movement speed to be rather fast.

Nearly all participants rated the subjective perception of the robotic support in this scenario as very comfortable or rather comfortable, while one participant perceived it to be neither pleasant nor unpleasant.

Furthermore, 100 percent of participants stated that they felt very safe while performing the semiautonomous robotic behaviours.

Interestingly, only two participants said they would prefer human assistance to be served a drink, while 55 percent of participants said they would prefer robotic assistance.

When quizzed about what aspects of the “serve a drink” scenario participants liked, participants cited the device’s smooth movements and precise and fast reactions. Most participants preferred to fully control the system as long as they were physically and cognitively able to do so. In the event of a physical or cognitive decrease, participants preferred the system to take over control and act autonomously.

However, the device was criticised for being unsuitable for home use due to its large size. One participant also highlighted the risk of spilling liquid, as the cup was served to them in a slightly skewed position. Another participant criticised the system for taking different paths to pick up and serve the cup.

In three cases, the system collided with the surrounding devices when returning to the starting position, which caused irritation among the participants.

2. Hand over a mobile phone

The “hand over a mobile phone” scenario was rated as very relevant or rather relevant for their everyday lives by nine respondents. One participant rated it as neither relevant nor irrelevant, and another participant rated it as rather not relevant.

All participants found the assistive device easy to use. However, participants had differing opinions on the speed of movement. Three participants rated it as very fast or fast, four participants rated it adequate, and the remaining four participants found the speed slow.

Almost everyone rated the robotic assistance as very comfortable or rather comfortable with just one participant rating it indifferently.

Regarding participants’ feeling of safety during the semiautonomous task execution, 100 percent of participants indicated that they felt very safe or rather safe.

Two participants said they would prefer human assistance for this task, while almost three-quarters would prefer the help of the robotic system.

When asked about what participants liked about the “hand over a mobile phone” task, careful pickup of the mobile phone, and fast and precise motion sequence over large distances were described as positive. In general, the task was described as being “close to reality”.

However, in a few cases, the phone was dropped rather than carefully put down during the delivery. In addition, participants emphasised that the scenario was only suitable for people who can still pick up and operate a phone independently.

3. Skin scratching

In total, nine participants rated the “skin scratching” scenario as very relevant or rather relevant for their everyday life. One participant each rated it as neither relevant nor irrelevant.

The ease of use of the control unit was rated as very easy or rather easy by all participants. However, participants gave mixed feedback regarding the speed of movement of ROBINA. Three participants found the speed to be very fast or rather fast, six rated it as appropriate, and two felt the speed was rather slow.

Robotic assistance was rated as very comfortable or rather comfortable by 10 participants, while one participant perceived it as rather unpleasant.

10 participants felt very safe during the semiautonomous task execution; one participant rated the feeling of safety as rather unsafe.

Two-thirds of participants said they would prefer robotic assistance for this task, and one participant indicated a preference for human assistance. The remaining participants did not state a preference.

When questioned about what participants liked about the “skin scratching” task, participants liked the quick satisfaction of solving an acute problem and the increase in privacy and independence. Moreover, participants perceived the scratching as pleasant, depending on the brush and skin type.

However, concerns were expressed about how practical the task was, especially around the facial area, alongside potential injury to the skin when the system picks up a brush.

The requirements for the correct positioning of the participant in relation to the ROBINA system were also viewed critically, because although this was plausible for safety reasons, it could not be implemented in everyday life independently by patients with ALS and limited mobility. In this respect, dependence on other people will remain.

4. Free manipulation

100 percent of the participants rated the “free manipulation” task as very relevant or rather relevant for their everyday life.

The ease of use of the control unit was rated by all but one participant as very simple or rather simple. That one remaining participant evaluated it as adequate.

The speed of movement was also considered differently in this scenario. Two participants perceived it as rather fast, six found it to be adequate, and three rated it as rather slow or very slow.

The robotic support was rated as very pleasant or rather pleasant by 100 percent of the participants.

Except for one participant, the subjective feeling of safety during the robotic executions was rated as very safe by all participants.

Looking at the preference for human or robotic assistance, two participants preferred human assistance for the “free manipulation” task, while six preferred robotic assistance. The remaining participants did not state a preference either way.

When discussing the positives of the “free manipulation” task, participants praised the precise movement control (ability to choose between small and large movements) and the sensitivity of the ROBINA system.

In contrast, participants criticised the device for not being able to adjust the movement speed, head control being strenuous, and the nonuniformity of the robot’s movements because they did not follow a straight line.

Overall study findings

Overall, the study found that the assistive robotic device was considered to be relevant for carrying out the four different tasks for those with ALS.

Most participants evaluated the operation of the system as easy and the semiautonomous robotic actions as pleasant. At the same time, most participants felt safe during the semiautonomous robot actions.

Differences existed, especially regarding the execution speed of the semiautonomous robot actions and the preference for human assistance over robotic support.

In general, users positively evaluated the semiautonomous robot capabilities, praising the precise and dynamic motion sequences and the careful picking up of objects.

However, at the same time, errors such as irregular motion paths, collision with equipment in the environment, and inaccurate pickup of objects became evident. Against this background, precise and reliable execution of semiautonomous robot motions and object manipulations and environmental and object recognition capabilities were key development requirements. Another central result concerns the execution speed, which should be customizable according to the user’s abilities. Generally, the participants desire a largely self-responsible control of the robotic manipulator. In contrast, semiautonomous robotic actions should be applied when the user’s physical abilities decline during the day (eg, owing to fatigue) or owing to the progressive course of the disease.