GB2256933A

GB2256933A - Means and method for indicating a person's balance

Info

Publication number: GB2256933A
Application number: GB9212845A
Authority: GB
Inventors: John Stephen Barton; Alan Miles Wing
Original assignee: Medical Research Council
Current assignee: Medical Research Council
Priority date: 1991-06-19
Filing date: 1992-06-17
Publication date: 1992-12-23
Anticipated expiration: 2012-06-17
Also published as: GB9113291D0; GB9212845D0; GB2256933B

Abstract

Apparatus for indicating a person's balance comprises an active weighing platform 1 and an adjacent, stationary platform 2 at the same level. An electrical signal from the platform 1 is fed to an amplifier 8 the output of which is connected to a meter 5 which has a pointer movable around a dial provided with markings at 0, 50 and 100. When a person stands with his two legs on the two platforms, respectively, the pointer indicates weight distribution or balance, that is the proportions of total body weight which are distributed between the person's two feet. A reading of 50 indicates an even weight distribution. <IMAGE>

Description

Title: Apparatus and Method for Indicating a Person 5 Balance Field of the Invention This invention relates to an apparatus and method for indicating a person's balance, ie the proportions of total body weight which are distributed between the person's two feet.

Background to the Invention It is important to be able to assess a person 5 balance, and to treat any imbalance, in a number of situations.

For example, individuals who have suffered a stroke tend not to distribute their body weight evenly between their two feet when standing. The same applies to individuals who have been fitted with an artificial leg or who have (or previously had) any disorder which causes them to stand with an uneven weight distribution. Such imbalance is in practice corrected by therapy, either with the assistance of a therapist or directly by the individual.

In all of these situations there is a need for a rapid means of indicating a person's balance, and the invention aims to meet this requirement.

Disclosure of the Invention According to one aspect the invention provides apparatus for indicating a person's weight distribution, comprising two adjacent platforms one of which is a weighing platform which produces an electrical signal representative of the weight on the weighing platform, display means which provides, by way of a visible reading, an analogue representation of the weight on the weighing platform, the display means having a first marking at a first amplitude and a second marking at a second amplitude which is half said first amplitude, and gain control means for varying the effective magnitude of the electrical signal fed to the display means, in use a person placing all his weight on the weighing platform and the gain control means being adjusted so that the display means shows a reading corresponding to the first amplitude and the person then placing his respective feet on the two platforms with the result that the reading of the display means shows, in relation to the second marking, the person's weight distribution.

The display means may be in any easily readable form such as an LED, but preferably includes a pointer pivotally movable around a dial, and in a preferred embodiment the second amplitude corresponds to the pointer pointing upwards (ie at the 12 o'clock position) so that by arranging the person to stand with his right foot on the weighing platform and his left foot on the other platform, the pointer is positioned to the right of the second marking if the person is applying a greater weight on his right foot, and the pointer is positioned to the left of the second marking if the person is placing a greater weight on his left foot. The position of the pointer thus provides a very direct analogue indication of body symmetry.The first marking may represent full scale deflection of the pointer and this first marking is preferably positioned at the three o'clock position on the dial, zero on the dial being at the nine o'clock position.

According to another aspect of the invention a method of indicating a person s balance comprises arranging for the person to stand on a weighing platform linked to a display means providing an analogue reading representing a visual indication of the weight on the weighing platform, the display means having a first marking at a first amplitude and a second marking at a second amplitude which is half said first amplitude, adjusting the display means to bring the indicated reading to the first marking, arranging for the person to stand with his respective feet on the weighing platform and on a further platform alongside the weighing platform and noting the indicated reading, in relation to the second marking, to provide an indication of balance.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic elevation of balance indicating apparatus according to the invention, Figure 2 is a side view of the apparatus of Figure 1, Figure 3 is a schematic electrical circuit diagram, and Figure 4 illustrates a possible modification.

Referring to Figures 1 and 2, the apparatus comprises two platforms 1 and 2, the platform 1 being an active weighing platform and incorporating a load cell which provides an electrical signal representative of the weight applied to the platform 1. The other platform 2 is a stationary platform which is arranged adjacent the platform 1 and at the same height. The two platforms 1 and 2 form a base from which projects a column 3 supporting a display and control console 4. The console 4 has a circular meter 5 (better shown in Figure 3) and a control knob 6.

The electrical signal from the weighing platform 1 is conducted up the support column 3 by means of an electrical connection 7 (Figure 3) to an amplifier 8 in the console 4. The output from the amplifier 8 is connected to the meter 5 which includes a pointer movable around a dial provided with markings at 0, 50 and 100.

Rotation of the knob 6 alters the effective gain of the amplifier 8 by varying the feedback characteristics around an amplifier component 9, the result being that the signal fed to the meter 5 is representative of the weight applied to the platform 1, subject to the gain control. A balance switch 10 is movable between two positions, in the first of which (illustrated) the gain adjustment means is brought into circuit and in the second of which the gain adjustment means is isolated and the meter 5 indicates weight (in imperial and/or metric) on the platform 1.

The apparatus is used to assist training of balance of a person who first stands with his full body weight on the active platform 1. The adjustment knob 6 is then rotated to alter the gain of the amplifier 8 so as to bring the pointer to the full scale deflection reading of 100. The person then stands with his right foot on the active platform 1 and his left foot on the static platform 2 and the meter reading is viewed. If the person is placing more weight on the right foot, the needle will settle to the right of the 50 marking but if the person is placing more weight on the left foot the needle will settle to the left of the 50 marking. The position of the needle, in relation to the 50 marking, therefore provides a very clear indication of any body imbalance.No calculations or calibrations are necessary because once the meter reading has been adjusted to the 100 marking when the person puts his full weight on the platform 1, the apparatus is set up to provide a direct analogue indication of body symmetry for that person. The apparatus can be implemented as a low cost modification to widely available home electronic weighing scales. The apparatus can be used in hospitals or clinics, as well as by individuals in their own homes.

The electrical signal from the amplifier 8 may be fed by a connection 11 to a computer.

Movement of the switch 10 to the second position changes the apparatus to an ordinary calibrated weighing system.

The connection to the meter 5 incorporates a switch 12 which normally occupies the position shown in Figure 3 but which is movable to an alternative position (shown in broken lines) for displaying an integrated representation of sway over a period of time. The circuit to achieve this is shown in Figure 4, where the switch 12 is again shown in its normal position in full lines and in its alternative position in broken lines.

Referring to Figure 4, the output from the amplifier 8 is fed through a normally open switch 13 to a differentiator 14 and an integrator 15, the output of which is fed to the display 5 when the switch 12 is in its alternative position. The circuit of Figure 4 is rendered operative by a push button 16 which is pushed, so as momentarily to close switch contacts, thereby to initiate the integration mode. When the push button 16 is momentarily closed, a first timer 17 and a second timer 18 are energised. The timer 17 acts to close the normally open switch 13 and, simultaneously, the timer 18 acts to change the switch 12 to its alternative position. The switches 12 and 13 are now in the opposite positions to those shown in Figure 4, and the circuit of Figure 4 is operative to supply an integrated representation of sway to the display 5.The timer 17 times out after a predetermined time, say 15 seconds, at which point the switch 13 reverts to its normally open position. The timer 18 times out after a longer predetermined time, say 20 seconds, so that there is a time interval (in this five seconds) during which the display 5 continues to show the integrated representation of sway after the switch 13 has opened. After the timer 18 has timed out, the switch 12 reverts to its normal position, and the display 5 reverts to the normal mode described with reference to Figure 3.

The circuit of Figure 4 thus differentiates, rectifies and integrates over a predetermined period of time (eg 15 seconds) the body weight-referenced measure of weight on the active platform. The resulting measure of.

fluctuations of weight distribution ("sway") may be displayed continuously to the subject as biofeedback to encourage stable standing or used (without feedback to the person on the device) as a diagnostic index of balance problems.

An LCD may provide a digital reading (with appropriate analogue conversion circuit) of weight distribution or sway. The reading would be useful for diagnostic purposes (but not for biofeedback).

The apparatus may be supplemented by a circuit providing stereo sound signals that represent right or left imbalance. This would be valuable to those with impaired sight.

A platform or step (for example 5cm above the ground or floor level) may be provided to assist a user to step onto the two platforms 1 and 2. This could be beneficial for an elderly or infirm user.

Claims

1. Apparatus for indicating a person's weight distribution, comprising two adjacent platforms one of which is a weighing platform which produces an electrical signal representative of the weight on the weighing platform, display means which provides, by way of a visible reading, an analogue representation of the weight on the weighing platform, the display means having a first marking at a first amplitude and a second marking at a second amplitude which is half said first amplitude, and gain control means for varying the effective magnitude of the electrical signal fed to the display means, in use a person placing all his weight on the weighing platform and the gain control means being adjusted so that the display means shows a reading corresponding to the first amplitude and the person then placing his respective feet on the two platforms with the result that the reading of the display means shows, in relation to the second marking, the person's weight distribution.

2. Apparatus according to claim 1, wherein the display means includes a pointer pivotally movable around a dial.

3. Means according to claim 2, wherein the second amplitude corresponds to the pointer pointing upwards (ie at the 12 o'clock position) so that by arranging the person to stand with his right foot on the weighing platform and his left foot on the other platform, the pointer is positioned to the right of the second marking if the person is applying a greater weight on his right foot, and the pointer is positioned to the left of the second marking if the person is placing a greater weight on his left foot.

4. Apparatus according to claim 3, wherein the first marking represents full scale deflection of the pointer and this first marking is positioned at the three o'clock position on the dial, zero on the dial being at the nine o clock position.

5. Apparatus according to any of the preceding claims, and including circuitry for providing, on the display means, a representation, integrated over a period of time, of weight distribution.

6. A method of indicating a person s balance, comprising arranging for the person to stand on a weighing platform linked to a display means providing an analogue reading representing a visual indication of the weight on the weighing platform, the display means having a first marking at a first amplitude and a second marking at a second amplitude which is half said first amplitude, adjusting the display means to bring the indicated reading to the first marking, arranging for the person to stand with his respective feet on the weighing platform and on a further platform alongside the weighing platform and noting the indicated reading, in relation to the second marking, to provide an indication of balance.

7. Means for indicating a person's weight distribution, or a method of indicating a person's balance, substantially as herein particularly described with reference to the accompanying drawings.