Promoting Visual Biofeedback through a Medical Device for Physical

Therapy and Physical and Rehabilitative Medicine

Carlos Alcobia

, Rui Costa

, Luís Ferreira

and Pedro Mendes

Instituto Politécnico de Coimbra, ISEC, DEM, Rua Pedro Nunes, Quinta da Nora, 3030-199, Coimbra, Portugal

Universidade de Aveiro, ESSUA, Campus Universitário Santiago 3810-193, Aveiro, Portugal

Sensing Future Technologies, Rua Pedro Nunes 3030-199, Bloco C, Coimbra, Portugal

Keywords: Visual Biofeedback, Medical Device, Physical Therapy, Balance, Load Transfer.

Abstract: The present paper synthesises the development of a medical device which promotes visual biofeedback for

Physical Therapy and Physical and Rehabilitative Medicine. After the identification of a specific need, a

solution extremely versatile with advantages for the patient and the health professional is presented. A brief

reference to its technical development and its performance is presented, introducing the visual biofeedback

interface and gathering a set of identified clinical applications. Finally, some possible further developments

are listed.

1 NEEDS’ IDENTIFICATION

The current models of intervention, in terms of

physical therapy, focus on manual therapy, physical

agents and movement therapies, usually on an

outpatient basis, in which individuals are subjected

to short period treatment sessions (30-60 minutes),

from Monday to Friday and long periods of

inactivity outside treatment. There are several health

conditions with strong repercussions in terms of

functionality, including changing the basic position

of the body in lying down position, going from lying

to sitting; maintaining balance when sitting, moving

from sitting to standing and walking. (Cheng et al.

2004; Terena and Taricco, 2009).

It is also noteworthy that motor learning requires

structuring activities into specific tasks with high

intensity training and a strong motivation of the

individual, which is not guaranteed with short and

nonspecific sessions. Motor training programs,

including balance and motor control should be

structured in order to enable the pro-activity of the

user, with or without supervision, but making a

workout several times a day possible.

Thus arises the need to design specific

equipment to enable individuals to train tasks/

activities included in the rehabilitation process and

that simulate global patterns of activity, such as

standing and sitting, which may be performed either

in the clinic or at home. Such equipment should also

have a low cost, be easy to understand, portable and

give the individual a real-time feedback on their

performance. These devices would be especially

suitable for individuals with changes in terms of

mobility, inability to change the basic position of the

body, get up and sit down, take a standing position

and walk, resulting from the aging process itself,

neurological, musculoskeletal or other injuries.

Currently, there are several solutions concerning

some of the features referenced. One can enumerate

a set of solutions currently available on the market

highlighted by some brands: platforms AMTI forces,

the Tetrax of Sunlight, the Medtrack of InBalance,

the product family balancing Neurocom, the Balance

Check of Bertec, the Wii fit of Nintendo, the

Kinectic of Xbox, among others. However the

solutions listed are extremely complex in terms of

interfaces, usability and interaction with the user.

Their own data and information resulting from the

use of such equipment are very technical, with

admirable precision and not directed to the user, only

the reach of scientific research centers, universities,

and some hospitals and not to the reality of a clinic

or a most common medical center and closer to the

community. In many cases, even the setups

associated with these equipments are very time

consuming and require a thorough knowledge of the

system. Exception is made to Wii fit of Nintendo and

the Kinectic of Xbox, since they are positioned for

293

Alcobia C., Costa R., Ferreira L. and Mendes P..

Promoting Visual Biofeedback through a Medical Device for Physical Therapy and Physical and Rehabilitative Medicine.

DOI: 10.5220/0004697002930298

In Proceedings of the International Conference on Physiological Computing Systems (PhyCS-2014), pages 293-298

ISBN: 978-989-758-006-2

 2014 SCITEPRESS (Science and Technology Publications, Lda.)

the domestic segment, have capacities very

interesting, very intuitive interfaces, but they are still

aimed at recreational leisure time. Thus, the authors

advocate the design of a device that is positioned

between the more technically oriented and more

recreational aspect, which is designed and the scope

of everyday life in a clinic or medical center

allowing these centers benefit from an important

technology for your business .

Translating the need into concrete requirements,

the development of a device with an automatic data

acquisition was intended. This device allows the

performance of several physical exercises, in which

it is possible for the user to have access to real-time

quantitative values about the exercises performed. It

is also intended that the information provided has

not only the function to re-educate the user

regarding his/her posture but also to motivate the

physical procedure that he/she should adopt in their

daily lives, as well as encourage their awareness

level of their postural control. Simultaneously it is

intended that such information supports the

healthcare professional attending the case, enabling

him to verify the behaviour of the user during the

exercise, thus being in possession of an additional

tool for the evaluation plan or recovery of several

users.

2 CHARACTERIZATION OF

THE MEDICAL DEVICE

The developed device comprises a chair and a

platform, both instrumented, and a display (Ferreira,

2012) (Figure 1).

Figure 1: Chair, platform and display.

It comprises a chair whose seat is divided into

two independent and instrumented quadrants,

allowing knowing the force distribution in each

quadrant and differentiating the load exerted on the

left or the right side. The chair also has an automatic

height adjustment and the arms’ position is also

adjustable.

The platform is divided into four independent

and instrumented quadrants, thus allowing

differentiating loads exerted on each of them.

The two quadrants comprising the seat and the

four quadrants that make up the platform each

contain four micro load cells attached at its ends.

The analogical signals from the micro load cells are

then sent to a module where they are amplified and

converted into digital signals and processed by a

microcontroller. The communication between the

application server (chair or platform) and application

client (computer and display) is made over Wi-Fi.

It is a training device for balance and motor

control that enables training in the position of sitting,

standing, as well as the analysis of movement get up

and sit down. Allows training in the antero-posterior

sagittal and rotational planes, whose operation is

based on the acquisition of the mass distribution on

the various support quadrants (seat and/or feet). Its

ability to provide real-time, visual biofeedback

directed to the user and the healthcare professional it

is also shown, which allows conveying real-time

visual objective data related to the exercises of

clinical practice performed with the device, through

software interfaces which have been specially

developed for this purpose. The visual biofeedback

is suggested to the patient and healthcare

professional through any display as long as it has an

associated processor running the same software. The

health professional collects information that is

sensitive in real time and can also store that

information in the database associated with the

software. Can even query it in the form of graphs

and tables in the software itself or simply print a

report.

This device allows, enhancing and intensifying

the process of recovery in gym. Consequently, it

stimulates the active participation of the individual,

obtaining a much higher yield in terms of the

recovery process, very difficult, if not impossible to

achieve with current conventional programs.

The applicability of the device is directly related

to its performance, which can be grouped into two

distinct categories: balance category and load

transfer category (Mendes, 2012). In the following

subsection reference is made to each category

presenting a set of specific exercises, its goals and

associated visual biofeedback interface.

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2.1 Balance

The balance condition assessments consist of

comparing in real time the amount of force exerted

on each measurement plane and verify that they are

within a tolerance margin that is defined by the

healthcare professional. If the individual is within

the tolerance zone, the visual biofeedback indicator

suggests the colour green, otherwise it suggests red.

Thanks to the visual biofeedback, the user can, in

real time, immediately correct the distribution of its

load through a balance mobile indicator. Thus, the

device allows evaluating the force distribution in

several planes and hence assesses: Sagittal Balance,

Antero-Posterior Balance and Global Balance.

Sagittal Balance refers to the sagittal plane that

pierces the human body and comprises a left and a

right side. The sagittal balance evaluation can be

performed in a sitting position and in a standing

position (Figure 2).

Figure 2: Exercise and visual interface representation.

Antero-Posterior Balance refers to the Antero-

Posterior plan that pierces the human body and

comprises the front and back side. Antero-Posterior

Balance assessment is performed in the standing

position (Figure 3).

Figure 3: Exercise and visual interface representation.

The Global balance refers to the sum of the

"sagital balance" and "anterior-posterior balance",

where the user has to control a uniform distribution

of his/her load in two different planes

simultaneously and is performed in a standing

position." (figure 4).

Figure 4: Exercise and visual interface representation.

2.2 Load Transfer

The information of the force distribution by the

several plans can be used in a different perspective

other that maintaining balance. It is very interesting

in a clinical practice to ask the user to transfer all

his/her load to one side, especially in cases of

recovery from a stroke and promote the load transfer

to the most affected side. In this perspective, visual

biofeedback suggests the use of a "filling bar" effect

as the load exerts on the measuring plane.

Following, an exercise is presented in which the

individual is asked to transfer their load to one side.

The exercise can be performed in a sitting or

standing position in the sagittal plane, i.e., between

the left and the right side (Figure 5).

Figure 5: Exercise and visual interface representation.

Another interesting way to promote load transfer,

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regarding the lower limbs, is an exercise in which

the individual in the seated position is requested to

transfer his/her load exerted on the chair to the lower

limbs (based on the platform), without getting up.

This exercise is particularly interesting for

enhancing muscle strength in the lower limbs

(Figure 6).

Figure 6: Exercise and visual interface representation.

The device also allows quantifying load

distributions in the sitting-standing and standing-

sitting movement in the sagittal plane, i.e., it is

possible to quantify the force that the user makes in

his left and right leg during the described movement

and also to know which limb he/she uses more

frequently. This information is graphically presented

and in this specific case is directed to the healthcare

professional (Figure 7).

Figure 7: Visual interface representation.

3 ADVANTAGES OF THE

MEDICAL DEVICE

The medical device described presents the following

advantages:

 Chair and platform set

The set of chair and platform forces allows

working several movements and positions and

obtaining objective data of various nature. The chair

also plays a key role for users with a more limited

degree of mobility and allows starting the process of

their recovery while still in the sitting position, as is

the case of strokes’ recovery. The chair may also

play a role of support and security to the user in their

recovery process as it allows situations of rest if the

patient needs it.

 Versatility

Although the greatest potential of the device is in

the joint operation between chair and platform, you

can use the equipment separately, by only using the

platform or chair, changing into a modular concept.

 Functionality

The device is designed to be easy to handle, and

is not demanding in terms of settings, so that its

potentials are always available in a functional, fast

and convenient way, referring to the reality of a

physiotherapy clinic or a physical rehabilitation

centre.

 Low learning curve

Handling the device, by health professionals,

does not require specific training or waste of time. It

should also be highlighted that it was developed

with healthcare professionals using as a preferential

factor for its development methodologies defined by

therapists and users. Result of several tests, it can be

seen that learning to handle the equipment is

significantly fifteen minutes.

 Use philosophies

The use of the device can be viewed in the

perspective of assessment, diagnosis and training.

Thus it can be used to evaluate, to define an

intervention plan, train and continually re-evaluate.

The device is currently undergoing certification

under ISO 13485 relating to medical devices.

 Patient’s autonomy

Another advantage lies in the fact that the

individual, in some training situations already

defined, have the ability to can use the equipment

alone or with the supervision of a family member,

not requiring the presence of a healthcare

professional.

 Freedom of exercises

Several categories of exercises are available and

their use is not static, since the healthcare

professional has the freedom to choose the

movements he/she deems relevant, i.e. the exercises

in the software interface do not limit the activity of

the healthcare professional. The healthcare

professional can still have free force measurements,

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without being associated with a protocol or pre-

defined exercises. The measurement of forces and

weighing free refers to the sensitive areas of the

machine, unlike the exercises which interfaces

signals from the six sensitive areas are processed.

 Management of exercises

A set of features that enable the exercises’

management is available: time, results, objectives,

difficulty regulation and recording data.

 Pro-active Rehabilitation Process

The Visual Biofeedback promoter interface is

designed to be very simple, intuitive, attractive and

easy to understand. Thus it promotes the user to

have a more active role as they are encouraged to

achieve goals for which they will strive to achieve,

perceiving them as a challenge.

4 APPLICATIONS AND

CLINICAL INDICATIONS

The fact that it is a device that aims to prevent the

dysfunction and/or enhance the ability of the

individual in performing specific tasks, such as

maintaining balance in a sitting position, get up and

down, and maintain balance while standing, allows

its applicability in all situations where these tasks

are compromised and/or are essential to perform

others. To sit and rise from a chair is one of the most

common activities of daily living, vital for assuming

and maintaining a standing position, to walk and

thus maintain the ability to perform day-to-day

activities, personal hygiene, and mobility, among

others. However, the ability to assume and maintain

a balanced sitting position is essential, without

which the other are compromised. This situation is

often compromised by a variety of pathologies, or

even by the aging process.

This equipment makes it possible to improve the

capacity of intervention by exercising a set of

neuromusculoskeletal functions such as:

 Function proprioceptive

 Functions of mobility and stability of joints

 Functions of strength and muscle tone

 Functions of muscular endurance

 Functions motor reflexes

 Functions of voluntary movement control

 Functions related to gait pattern

 Sensations related to muscles and movement

functions

In mobility stands out:

 Changing the basic position of the body

 body position maintenance

 Auto transfers

 Balance sitting

 Walk

Thus, this device allows a wide applicability

enhancing rehabilitation of functional disorders

caused by neurological pathologies,

musculoskeletal, motion diseases and/or loss linked

to aging.

The improvement found in the individual's

performance of the tasks may still be considered

extremely important in the prevention of falls in an

elderly age, strongly associated to tasks like sitting,

standing and walking. The gains in terms of balance

and motor control may also be relevant in the

recovery or sports performance.

It is also noteworthy that the improvement in

terms of the tasks listed, is important in reducing the

difficulties that the individual may have in executing

activities, as well as the problems that an individual

may face when involved in real-life situations.

The training methodology and the active

participation of individuals in the program may also,

in an indirect way, enhance the improvement of

other functions, such as cardio respiratory functions

and mental functions such as improving levels of

attention, concentration and memory.

5 FURTHER DEVELOPMENTS

The versatility of the described device opens a huge

window for future developments at various levels,

either in its improvement and performance, or as

complement to other clinical techniques. A set of

plans in the medium short to medium term for the

device are presented:

 Forecast of falling risk

The fact that the device allows to quantify a

number of objective data, lead to its use in a pilot

study that relates the data from the device with the

Berg and Tinetti balance scale through multiple

linear regressions and artificial neural networks. The

results were very satisfactory and indicate a strong

relationship. The data, methodology and results can

be found at “Modelação Numérica do Índice de

Tinetti e de Berg” (Mendes,2012). It is expected that

in the near future the device may have an application

that provides the fall risk of the individual. There is

an ongoing larger study to investigate this trend in

more detail.

 Sound Feedback

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At the moment, the only form of feedback focuses

on vision. In the future we intend to extend the

feedback to the hearing ability, allowing blind or

individuals with some degree of vision impairment

to benefit from the device potential.

 Association image capture

Since kinematic consists in measuring motion

without considering the forces involved thereby

serving to calculate displacements, velocities and

linear and angular accelerations present in the

observed motion, its association with the referenced

device will allow a better understanding of the errors

in movement patterns and the definition of an

intervention program.

REFERENCES

Cheng, P., Chen, C., Wang, C., & Hong, W. (Janeiro de

2004). Leg Muscle activation patterns of sit-to-stand.

movements in stroke patients. American Journal of

Physical Medicine & Rehabilitation , 83, pp. 10-16.

Terena, S., & Taricco, M. (3 de Junho de 2009).

Comparação das estratégias musculares entre dois

grupos etários diferentes no movimento de passar de

sentado para em pé. Acta fisiatrica , pp. 105-109.

Ferreira, Luís A. G., Fevereiro de 2012. Tese de Mestrado.

Desenvolvimento e concepção de um sistema de

medida para a avaliação do equilíbrio humano,

Universidade de Coimbra.

Mendes, Pedro M. J. L., Fevereiro de 2012. Tese de

Mestrado. Modelação Numérica do Índice de Tinetti e

de Berg, Universidade de Coimbra.

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