GB2409278A - Handheld galvanic skin response (GSR) biofeedback device - Google Patents

Abstract

A biofeedback apparatus includes a handheld graphic display showing an animated sequence, and a pair of contacts to measure skin resistance. The display is altered in response to measured resistance or change in resistance, enabling a visual distinction to be made between increasing skin resistance and decreasing skin resistance. The apparatus is for the treatment of epilepsy. The apparatus may be in the form of a PDA or palmtop computer and may store and communicate data. Other parameters such as heart rate and EEG can additionally be measured.

Description

APPARATUS AND SYSTEMS FOR THE TREATMENT OF EPILEPSY

This invention relates to apparatus and systems for the treatment of sufferers from epilepsy.

The effects of epilepsy in sufferers vary widely, the only common feature being the occurrence of epileptic seizures, which are characterized by convulsions and, in severe cases, loss of consciousness. But the frequency and severity of such occurrences varies very widely, as does the ability of sufferers voluntarily to control them, or to detect an impending occurrence.

The potential dangers of such occurrences have led to very substantial efforts being made to find a cure, or if not a cure then palliative or alleviative measures, for treating epilepsy, and there is a very substantial body of research which has been carried out, which has led to an ability to treat epilepsy in many sufferers, though the effectiveness of such treatment tends also to vary widely.

There is now a large range of synthetic drugs available which affect sufferers in different ways. In a substantial proportion of cases, improvements in management of epilepsy for an individual patient can be achieved, but this - 2 tends to be accompanied by considerable side effects and accordingly drug- based management of epilepsy is not seen as a universally positive form of treatment.

It has long been known that the occurrence of epileptic seizures, and their strength and frequency, correlate with mental state, and accordingly treatment programmes for an individual sufferer may well include mental training or conditioning as well as the physical administration of therapeutic drugs.

Despite efforts using both drugs and training, there seems to be a proportion of sufferers which do not respond well to either approach; 30 percent of sufferers may be classified as drug resistant and prior approaches to training have not produced substantial improvement in most sufferers.

It has now been surprisingly discovered that in at least a substantial proportion of these difficult or refractory cases of epilepsy, improvements can be made if they are subjected to biofeedback training which is designed to achieve an increase in vigilance or awareness, as reflected by changes in galvanic skin response.

It has long been known that galvanic skin response, conventionally measured by the resistance between two electrodes applied spaced apart to the skin, varies with the degree of alertness or relaxation of the subject. This phenomenon has been used in the past to assist in training people to relax.

WO 93/02622 describes apparatus for assisting relaxation in which a screen display showing a computer-generated animation is viewed by a user whose galvanic skin response is continuously monitored. As the resistance between the electrodes changes, so the animation may be controlled by a suitable programme to give the user a directly perceptible indication of whether they are becoming more relaxed or more tense, for example by seeing whether an animated fish seen against an underwater landscape is swimming to the i - 3 left or to the right. After some practice, users learn to be able to control the movement seen on screen to be predominantly in the desired direction corresponding to greater relaxation, i.e. they learn to relax.

It has been found [Nagai, Goldstein, Fenwick, Trimble, Effect of Galvanic Skin Response (GSR) Biofeedback Treatment in Patients with Epilepsy; British Neuropsychiatry - Annual Meeting February 2003] that epilepsy sufferers can be materially assisted by way of biofeedback training. If, in each of a series of training sessions, at least the galvanic skin response of the sufferer is monitored, while an animated display is viewed by the sufferer, and the sufferer is requested, during each session, to influence the animation in a way which corresponds to a decrease in skin resistance, it is found that a substantial improvement in the condition of sufferers from epilepsy can be achieved, including in those cases which appear to be resistant to treatment with any of the currently available range of anti epileptic drugs. It is believed that one way in which the GSR biofeedback acts to reduce epileptic seizures is that it acts to effect cortical potential changes. It is already known that the cortical potential change is crucial for seizure occurrences (Chatrian G. E. , Somasundaran M. and Tassinari C.A.

(1968) DC-changes recorded transcranially during "typical" 3sec spikewave discharges in man. Epilepsia 9: 185-209; Kuda K. (1977) The effect of diazepam, chlorpromazine and amovarbital on the contingent negative variation. Folia Psychiatr Neurol Jpn, 31(1): 77-87; Rockstroh B., Elbert T., Lutzenberger W. and Altenmuller E. (1991) Effect of the anticonvulsant benzodiazepine clonazepam on event-related brain potentials in humans.

ElectroencephalogrClin Neurophysiol, 78(2): 142-149; Rockstroh B., Elbert T., Birbaumer N., Wolf P., Duchtingroth A., Reker M., Daum I., Lutzenberger W. and Dichgangs J., (1993) Cortical self-regulation in patients with epilepsy, Epilepsy Research, 14: 63-72).

The treatment is preferably carried out as a series of regular sessions spaced over a period of 20 to 60 days, each session lasting at least 10 4 minutes, but usually no longer than 40 minutes. During each session the subject tries to follow the instruction to make the animation reflect a decrease in skin resistance by increasing their own vigilance or alertness, but preferably without recourse to physical activity, merely by mental activity.

The effects of such training do not fade rapidly. In some cases, there may be effective permanent improvement, while in others it may be desirable to repeat a training procedure, but the intervals appropriate for such repetition may vary very widely from one case to another. However, in most cases, a or period of several months can elapse after the training during which both the frequency and severity of seizures is reduced. The reduction in frequency is thought to stem, in part, from measurable changes in the brain which are not consciously perceptible by the sufferer. In addition, however, the severity of seizures is thought to be decreased at least in part voluntarily by conscious effort on the part of the sufferer who, when they feel a seizure is imminent, can call back to mind the memory of the training sessions, which seems to decrease the severity of the seizure, or indeed avoid its occurrence.

The simplicity of the biofeedback technique used, and the availability of low power consumption compact visual display devices, give rise to the possibility of providing sufferers with apparatus for use in treating epilepsy which can be easily and quickly deployed when desired by the sufferer with a view to improving their condition.

Thus, in accordance with the present invention, there is provided biofeedback apparatus consisting of a handheld graphic display adapted to show an animated sequence, electronic drive means for causing such display to show the sequence, a pair of contact members adapted to be placed spaced apart against the skin, and programme means to drive the animated display in accordance with the resistance detected between the contact members when so applied, or with the change in such resistance over time, in such a fashion that a clear visual distinction may be observed in the animated display between high or rising resistance and low or decreasing resistance.

Such apparatus may be configured similarly to a palmtop computer or PDA (personal digital assistant) device of type well known in the marketplace.

Indeed, if an existing palmtop computer or PDA has an appropriate input channel, it may be programmed appropriately to accept input from a device - adapted to provide a signal representative of, and varying with, galvanic skin response. The original programming of a PDA or like handheld device may be achieved using any appropriate mechanism. For example, an intending user may be able to download a fully featured software programme from the Internet to his or her PC, which then in turn programs the handheld device in known standard fashion.

The programme may additionally include record-keeping functionality enabling a record of use to be made over a period of time and subsequently recovered for analysis. Thus, a sufferer may be provided with the ability rapidly and easily to carry out an impromptu further training session when desired, and the time and date of such session can be stored for later analysis by the physician in whose care the sufferer is. Especially if the sufferer can input to such a record details of whether a seizure was avoided entirely or if not how severe it was, this can provide a very valuable log of the sufferer's condition, thus enabling the physician to monitor and treat the sufferer better. In addition, the use of such apparatus enhances the perceived degree of control over their own condition exerted by the sufferer, which is thought further to improve the management of the condition.

In a further development of the apparatus according to the present invention, such apparatus may be provided with communications functionality enabling real time data or stored data to be transmitted to a remote location. A variety of known techniques may be applied. For example, the apparatus may be provided with message-sending functionality using a mobile - 6 telephony network - triggered consciously by the sufferer or automatically a suitable message may be transmitted to a central monitoring computer system, which may itself be provided with analysis software to enable the sufferer's condition to be regularly and frequently monitored and analysed, and, e.g. to prompt a call-up to arrange a visit to the physician or clinician in appropriate circumstances. Indeed, the system may be, if desired, immediately responsive and interactive: the system may send back to the apparatus instructions to the user - either audible or screen-displayed - with a view to avoiding or better managing an impending seizure.

An alternative system which could be implemented would be regular or automatic realtime downloads of information from such apparatus into the sufferer's PC, for example using bluetooth technology to enable the apparatus to communicate with the PC, with the sufferer then sending a logfile - e.g. as an email attachment - to their medical advisers.

As can be easily appreciated, such apparatus may be analogous to the apparatus used in a clinical setting, e.g. in an outpatient department, to provide the sufferer with the initial training in management of their condition according to the invention. In the case of apparatus for use in a clinical setting, however, the apparatus may be designed to record other patient data during training sessions. For example, clinical use apparatus may include appropriate sensors, evaluation circuitry and analysis programmes to monitor brain activity, for example a standard EEG record may be provided, enabling the correlation between slow cortical potential change and skin resistance to be studied, or to monitor other physiological parameters such as heart rate or breathing rate.

Indeed, in a clinical setting, the physician may be able to assess the susceptibility of any particular sufferer to changes in their physiological, psychological or emotional state, and tailor both biofeedback training sessions and downstream online monitoring using communications technology as described above, to match the needs of the sufferer in question. - 8

Claims (7)

1. Biofeedback apparatus consisting of a handheld graphic display adapted to show an animated sequence, electronic drive means for causing such display to show the sequence, a pair of contact members adapted to be placed spaced apart against the skin, and programme means to drive the animated display in accordance with the resistance detected between the contact members when so applied, or with the change in such resistance Or over time, in such a fashion that a clear visual distinction may be observed in the animated display between high or rising resistance and low or decreasing resistance.

2. Apparatus according to Claim 1 and configured as a palmtop computer or PDA.

3. Apparatus according to Claim 1 or 2 wherein the programme means additionally includes record-keeping functionality enabling a record of use to be made over a period of time and subsequently recovered for analysis.

4. Apparatus according to any one of Claims 1 to 3 and including communications functionality enabling real time data or stored data to be transmitted to a remote location via a wide area communications system.

5. Apparatus according to Claim 4 and including means adapted to actuate message-sending functionality using a mobile telephony network either when triggered consciously by the sufferer or automatically.

6. Apparatus according to Claim 4 or 5 and including means to display on screen a return message sent from the remote location.

7. Apparatus according to Claim 1 and substantially as hereinbefore described.