GB2399886A

GB2399886A - Identifying degenerative brain disease using EEG or EMG measurements

Info

Publication number: GB2399886A
Application number: GB0306936A
Authority: GB
Inventors: Andrew Paul Bowditch; Thomas Micheal Mann; Peter Colin Pearce; Elizabeth Ann Marie Scott
Original assignee: UK Secretary of State for Defence
Current assignee: UK Secretary of State for Defence
Priority date: 2003-03-26
Filing date: 2003-03-26
Publication date: 2004-09-29
Also published as: GB0306936D0

Abstract

Early detection of degenerative brain disorders in humans and animals (e.g. BSE, scrapie, CJD) is carried out using EEG or EMG measurements. A sensor device 1 removably attached to a test subject measures the brain or muscular electrical activity of the subject, and wirelessly transmits the measured data to a processor 2. The measured data is compared with reference data taken from diseased subjects in order to determine if the test subject is infected with a degenerative brain disease. Processing may include frequency analysis and use of Fast Fourier Transform (FFT). Alternatively the data comparison and preclinical indication of disease may be carried out by a human operator by inspection of a visual representation of the data.

Description

Diagnostic Anuaratus This invention is concerned with means for analysing

for the presence of degenerative brain diseases such as BSE and scrapie in animals and CJD in man s BSE and scrapie are fatal diseases which affect livestock and have caused extensive damage in farming and related industries. These diseases have been linked to new variant CJD in humans.

If the presence of such diseases is suspected within a herd or flock, it is of paramount importance that the suspect animal or animals are isolated from the remainder without delay. There is, therefore, a need for means of identifying early preclinical indicators of these diseases. Moreover, it would be desirable to identify the presence of disease in man at as early a stage as possible to maximise opportunities for clinical intervention.

While formal diagnosis of such diseases may require the intervention of qualified medical or veterinary personnel, the current invention provides a means of identifying early indicators which facilitate optimal intervention and which could be used by personnel who are not qualified medical or veterinary practitioners.

Given that BSE and the like may take years to manifest itself in the observable behaviour or an infected animal, and there is no accepted method of confirming infection other than by examining the brain of a slaughtered animal, it has been suggested that the only safe approach to combating the disease is widespread slaughter. Inevitably, on implementation of such a policy, there will be many animals slaughtered that are not infected.

Therefore an invention that provides an aid to estimating the likelihood that an animal is infected and hence whether it should be slaughtered represents a significant advance in the art.

A common feature of the type of disease with which this invention is concerned is that neural and muscular function is compromised.

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The electroencephalogram (EEG) reflects the electrical activity of populations of neurones in the brain and itrecords positive/negative fluctuations in the microvolt range ((50-200) x 10-6 V). EEG recording is state dependent and reflects ongoing brain activity in that it changes as a result of parameters such as age, sleep stage and cerebral dysfunction. In man, EEG recordings are generally used to assess brain function in conditions such as epilepsy and to monitor sleep dysfunction in this and other conditions.

The electromyogram (EMG) reflects the electrical activity of muscles. At rest, muscles are electrically quiescent. When stimulated, electrical activity increases and subsequently declines. EMG measurements are used to assess muscle weakness or wasting. This can result from either nerve or muscle impairment In such circumstances, characteristic alterations of the electrical signals can be observed.

UK Patent Application no. 0110222.7 (Publication no. GB 2375 012) describes a biotelemetry monitoring system for use in collecting monitored data from athletes in training. The system described therein includes an individual data monitoring sensor for mounting on a subject under study. The sensor includes surface electrodes and means for onward transmition of data gathered thereby.

According to this invention, apparatus for identifying early indicators of degenerative brain disease in an animal or human subject comprises means for acquiring test data representing brain or muscle electrical activity of the subject and means for providing an indication of whether the subject is infected, depending on whether the test data are normal.

In a preferred embodiment the means for acquiring test data includes means for wireless transmission of said test data. More preferrably the means for acquiring test data is adapted for temporary fixing on the subject body.

A further preferred embodiment includes means for storing reference data representing brain or muscle electrical activity of infected animals or humans; processing means for comparing the two sets of data and means for providing an À .* À . À e À À À À À À À À À À À À À À À À À À À À À À * À indication of whether the subject is infected depending on the result of the comparison.

The processing means could include means for subjecting the test data to a fast fourier transform; means for grouping the result of said transform into frequency bands and means for calculating the relative power in each band.

In another embodiment of the invention, which offers advantages of simplicity, the apparatus further comprising means for providing a visual representation of the test data and the means for providing an indication comprises a human operator.

The reference data could comprise EEG or EMG recordings although this should not be seen as limiting.

According to a second aspect of the invention, a method of identifying early indicators of degenerative brain disease in an animal or human subject comprisies the steps of acquiring test data representing brain or muscle electrical activity of from the subject and providing an indication of whether the subject is infected depending on whether the test data are normal.

Preferrably the method further comprises the steps of storing reference data representing brain or muscle electrical activity of infected animals or humans; comparing the two sets of data and providing an indication of whether the subject is infected depending on the result of the comparison.

More preferrably the method further comprises the steps of subjecting the test data to a Fast Fourier transform; grouping the result of said transform into frequency bands and calculating the relative power in each band.

The invention will now be described with reference to Figure 1 which illustrates, in schematic form, an example of how the invention might be implemented, and figure 2 which shows the results of the analysis of the EEG of three groups of animals (error bars represent the standard error of the mean).

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Àe À À À Referring to Figure 1, reference data and test data (i.e. data obtained from an animal under investigation) may be collected using a sensor 1 such as the individual data monitoring sensor described in GB 2 375 012. . The electrodes used therewith are modified/substituted according to subject under investigation.

This device has the advantage of compactness and, after attachment to the animal e.g. by strapping, can transmit data without the need for physical connection to the processor 2.

The construction of alternative devices capable of acquiring and transmitting data is within the skills of a competent engineer.

By collecting data from animals or humans that are known to be affected by a particular disease, it is possible to derive reference data having features whose presence in test data may be taken as an indicator of the presence of that disease.

Processor 2 includes means for receiving the data from device 1 and for storing both reference data and test data.

Processor 2 also includes the computing capacity necessary to compare the reference and test data and providing an output which is dependent on the result of that comparison.

The output could be used to control, for example, an LED display which indicates the presence or absence of disease.

In an alternative embodiment, processor 2 includes means for producing a visual representation of the test data and the comparison is carried out by means of inspection by an operator. By referring to reference data, the operator is able, to recognise features in the test data which indicate the presence of disease.

Referring to figure 2, brainwave (EEG) recordings were taken from 12 cows, five of which were normal (controls), five had been infected either orally or by ICV injection with Bovine Spongiform Encephalopathy (BSE) but showing no signs c...

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eve À À (preclinical) and two had been diagnosed by veterinary surgeons as showing clinical signs of BSE. The EEG was measured from the shaven forehead of each animal using the CBS5000 biopotenial recording system (Retech Electronics) and stored on hard disc via a Micro1401 (available from Cambridge Electronic Design Ltd. (CED), Science Park, Milton Road Cambridge CB4 MULE). Data were analysed using a Spike 2 (CED) customised script. The analysis consisted of removing artefacts from the recording and then subjecting the resultant waveform to Fast Fourier Transform (FFT) analysis. This analysis outputs the relative frequency components of the waveform in terms of power (pV2). These frequency components were then grouped into bands (Delta: 0-3.9Hz, Theta: 4-.9Hz, Alpha: 8-11.9Hz, Beta 1: 12-23.9Hz and Beta 2: 24-39.9Hz) and the relative power (%) in each band calculated.

The results show an obvious change in n=2 animals displaying clinical signs and that an indication of the presence of pre-clinical BSE is also possible (data lying midway between controls and those showing clinical signs). Those animals with pre-clinical and clinical BSE showed a slowing of the background EEG represented by a rise in the %Mean Power in the 4-8 Hz frequency bin (Theta) and a reduction in the Beta 1 bin (12-24Hz).

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Claims

Claims 1. Apparatus for identifying early indicators of degenerative brain

disease in an animal or human subject, comprising: means for acquiring test data representing brain or muscle electrical activity of the subject and means for providing an indication of whether the subject is infected depending on whether the test data are normal.
2. Apparatus according to claim 1 where the means for acquiring test data includes means for wireless transmission of said test data.
3. Apparatus according to claim 1 or 2 where the means for acquiring test data is adapted for temporary fixing on the subject body.
4. Apparatus according to any preceding claim and further comprising means for storing reference data representing brain or muscle electrical activity of infected animals or humans; processing means for comparing the two sets of data and means for providing an indication of whether the subject is infected depending on the result of the comparison.
5. The apparatus of claim 4, where the processing means comprises means for subjecting the test data to a fast fourier transform; means for grouping the result of said transform into frequency bands and means for calculating the relative power in each band.
6. The apparatus of claim 1 where the means for providing an indication comprises a human operator and further comprising means for providing a visual representation of the test data.

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7. The apparatus of any preceding claim where the reference data comprises an EEG.
8. The apparatus of any preceding claim where the reference data comprises an EMG.
9. A method of identifying early indicators of degenerative brain disease in an animal or human subject comprising the steps of acquiring test data representing brain or muscle electrical activity of from the subject and providing an indication of whether the subject is infected depending on whether the test data are normal.
10. A method according to claim 9 and further comprising the steps of storing reference data representing brain or muscle electrical activity of infected animals or humans; comparing the two sets of data and providing an indication of whether the subject is infected depending on the result of the comparison.
11. The method of claim 10, further comprising the steps of: subjecting the test data to a fast fourier transform; grouping the result of said transform into frequency bands and calculating the relative power in each band.

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