JP5097994B2 - Brainstem dysfunction detection method, system, and program - Google Patents

Description

The present invention relates to an auditory brainstem reaction (ABR (Auditory
Brain-stem Response), auditory brainstem evoked potential (BAEP (Brainstem auditory
evoked potential). Hereinafter, in this application, the term “auditory brainstem reaction” is unified. ) Waveform data detection method, system, program, and the like. More specifically, the present invention relates to a brainstem dysfunction detection method, system, program, etc. for acquiring auditory brainstem response measurement data from a sedated animal and detecting a specific brainstem dysfunction such as BSE based on the data. .

  In the medical field in humans, an examination of an auditory brainstem reaction is widely performed as a detection / determination means such as an auditory nerve tumor, disturbance of consciousness, multiple sclerosis, brain death, and hearing loss (newborn hearing test).

  The auditory brainstem reaction refers to a change in the potential of the brainstem portion when sound stimulation is applied to the subject from the ear. In the case of a healthy person, electrodes are attached to a predetermined part of the scalp, sound stimulation is applied from the ear, and the potential of the brainstem part is recorded over time. A waveform having a peak is obtained. This waveform is a detection of a change in potential that occurs when sound stimulation is transmitted through the cochlear nerve and brainstem auditory tract. In humans, the origin of each potential peak has been clarified. Each peak is represented by Roman numerals (I to VII).

  Subject lies on his back in a shielded room, wears electrodes on his scalp, and wears headphones on his ears. Then, with the eyes closed at rest, a sound stimulus is applied from the headphones, and the potential is recorded from the electrodes.

  Click sounds are most often used for sound stimulation. In general, the stimulation frequency is 10 to 30 times / second, the duration of stimulation is 0.1 to 0.2 milliseconds, and these stimuli are added 500 to 2,000 times to obtain a waveform of the auditory brainstem response. Get.

  In the examination of the auditory brainstem reaction, a stable waveform is obtained that is not easily affected by consciousness or sleep state and has extremely good reproducibility. In addition, as described above, the origin of each waveform has been clarified and there is also the reproducibility of each peak, so it is used as a highly reliable data for detection and judgment of auditory nerve / brain stem dysfunction, etc. Yes.

  On the other hand, in animals other than humans, for example, large animals such as cows and horses, (1) It is difficult to enter a shield room and remain in the room for a certain period of time. (2) Perform general anesthesia treatment In some cases, special veterinary medical equipment is required, the burden on animals is large, and the risk to the measurer is increased. Little has been tested for brainstem response.

  However, there are many auditory nerve / brain stem dysfunctions in large animals.

  BSE (bovine spongiform encephalopathy) is mentioned as an example of the disease accompanied by brainstem dysfunction of large animals. BSE, also called mad cow disease, is caused by accumulation of abnormal prion protein in the brain and spinal cord. At the beginning of the onset, no noticeable symptom appears to the extent that behavioral changes occur, but it gradually becomes hypersensitive to sound and contact, and when the disease progresses further, it becomes impossible to stand up, and convulsions.

  For BSE testing, methods such as histopathological examination, immunohistochemical examination, Western blotting, etc. are used after the death, using brain tissue material of post-mortem cattle. Detection of abnormal prion protein by immunohistochemical examination or Western blotting has been carried out. Various attempts have been made to improve the detection sensitivity of abnormal prion protein. However, at present, no prion detection has been confirmed from easily collected biomaterials such as blood and urine, and thus a technique for detecting and diagnosing BSE before life has not been established.

  On the other hand, cattle diseases that show inability to stand and gait abnormalities include, for example, Haemophilus somnus infection, cerebral cortical necrosis, Downer syndrome, and the like. is required.

  Accordingly, there is a need for means for detecting the presence or absence of BSE in a living state without being killed.

  As diseases associated with brainstem dysfunction such as large animals, there are various brainstem dysfunctions other than BSE, including auditory nerve tumors, consciousness disorders, and hearing loss. However, for large animals and the like, it is difficult to maintain a resting state according to the examiner's intention, so brain brain function tests are rarely performed. Accordingly, there is a need for means for examining and determining brain stem function in a simple and minimally invasive manner.

Examples of the related documents of the present invention include the following.
Patent Document 1 describes a technique for diagnosing the presence of cochlear edema using an auditory brainstem reaction, and Patent Document 2 describes an acoustic nerve tumor detection means that uses a stacked induction band ABR amplitude. Patent Document 3 describes an evoked potential test apparatus including a Wavelet conversion unit that performs Wavelet conversion on data based on an auditory brainstem reaction. Patent Document 4 describes a method for diagnosing infectious spongiform encephalopathy by mass spectrometry. Patent Document 5 describes an ear coupler used for a human auditory brainstem reaction test.

In addition, the present inventor has recently reported that an auditory brainstem reaction can be obtained even in cattle by performing sedation with xylazine (see Non-Patent Document 1).
JP 2005-349198 A JP-T-2002-514457 JP 2006-239096 A JP-T-2005-502882 Japanese Patent Laid-Open No. 11-276460 Shozo Arai, “Brainstem auditory evoked potentials in cattle sedatedwith xylazine”, The Canadian Journal of Veterinary Research 2008; 72: 287-290

  As described above, for large animals, etc., (1) it is difficult to enter a shielded room and remain in that state for a certain period of time. (2) When performing general anesthesia, special veterinary equipment is required. In the clinical field, auditory brainstem reactions are rarely examined for reasons such as a heavy burden on animals and an increased risk to the measurer, and (3) large artifacts due to body movement.

  On the other hand, there are various diseases associated with brainstem dysfunction in large animals. Therefore, there is a need for a means for detecting brainstem dysfunction in these animals in a simple and minimally invasive manner.

  Accordingly, the main object of the present invention is to provide a means for detecting a specific brainstem dysfunction in a large animal or the like in a simple and minimally invasive manner.

  As described above, the present inventors have succeeded in obtaining an auditory brainstem reaction from a large animal by applying a sedative treatment to the animal.

  In addition, this time (1) newly developed ear restraint for animals, reduced noise derived from electromyogram, and (2) by adopting the electrode needle with a diameter suitable for each animal, We succeeded in acquiring auditory brainstem responses from large animals more easily, accurately and stably.

  When these methods were used to examine the auditory brainstem response for diseases associated with animal brainstem dysfunction, it was newly found that the waveform of a specific brainstem dysfunction is different from that of a normal individual.

  Therefore, the present invention provides a brainstem dysfunction detection method for acquiring waveform data of an auditory brainstem reaction from a sedated industrial animal and detecting a specific brainstem dysfunction based on the data.

  For example, after acquiring waveform data of an auditory brainstem response in a normal individual and / or an individual suffering from brainstem dysfunction as reference data in advance, acquiring waveform data of an auditory brainstem response from a sedated test animal, By calculating the waveform difference (difference), it is possible to easily and accurately detect the morbidity of a specific brainstem dysfunction.

  In addition, the present invention is useful as a means for detecting morbidity such as BSE before birth. As described above, BSE currently has only detection means using the brain tissue material of post-mortem cattle, and a technique for detecting BSE before life has not been established. In contrast, the present inventors have newly found waveform data of an auditory brainstem response unique to BSE. Therefore, according to the present invention, it is possible to detect the presence or absence of BSE in a living state before killing. That is, the present invention is a simple and minimally invasive brain stem dysfunction detecting means.

  In addition, the present inventors function as a sound stimulus generating means for generating sound at a predetermined sound pressure level and a predetermined interval, an electrode attached to an animal and acquiring an auditory brainstem reaction, a control unit, and a power source An auditory brainstem reaction detection system (or device) having at least a portable computer has been developed.

  In this system (apparatus), by using a configuration in which a portable computer or the like is used as a power source, a power source and a ground are unnecessary, and a power transformer and the like can be omitted from the configuration. For this reason, the entire system (device) can be made compact in size to the extent of an attache case and can be reduced in weight.

  In general, in large animals, it takes a lot of labor and time to bring each individual from a livestock farmer into the examination room of a livestock hygiene center or animal hospital, fix the individual, and perform various measurements. . In particular, it is substantially difficult to sequentially inspect and measure a plurality of individuals owned by a specific livestock farmer.

  On the other hand, in the case of this system (device), since it is compact and portable, it is possible to carry the system (device) into a livestock farm, etc. without having to transport each individual to a livestock hygiene center. Therefore, measurement and analysis can be performed. In addition, since no power supply or grounding is required, equipment can be transported, measured and analyzed at any place, such as outdoors in pasture fields. That is, by using this system (apparatus), the auditory brainstem reaction can be measured easily, at low cost, with low labor, and at any location. This system (apparatus) can be used not only for measuring large animals such as cattle and horses, but also for measuring auditory brainstem responses in other industrial animals such as pigs, sheep and goats, and pets such as dogs and cats.

  According to the present invention, it is possible to detect a specific brainstem dysfunction in various animals in a simple, highly accurate and minimally invasive manner.

<Acquisition of auditory brainstem response in large animals>
In large animals, as in humans, electrodes are attached to a predetermined part of the head of the test animal, sound stimulation is applied from each of the left and right ears, and the evoked potentials of the cranial nerves are recorded over time, and the auditory brainstem reaction is performed. get.

  When a sound stimulus is applied from the left and right ears, the stimulus is transmitted to the brain stem via the auditory nerve. The time from the application of the sound stimulus to the transmission of the stimulus to each part of the auditory nerve and brainstem is almost constant for each part. Therefore, the function of each part of the brain stem can be analyzed by recording the evoked potential transmitted from the auditory nerve to the brain stem over time for each of the left and right.

  In the measurement of the auditory brainstem response in large animals, it is better to pre-administer a sedative and hold the animal in a standing and resting state to perform the measurement.

  In the case of large animals, unlike humans, it is difficult to keep the posture of an individual the same for a certain time according to the intention of the measurer in the measurement of the auditory brainstem response. On the other hand, if general anesthesia treatment is performed at each measurement, a dedicated veterinary medical facility is required, the burden on the animal is large, and the risk of the measurer increases. Further, when measuring a plurality of individuals, it is not realistic to perform anesthesia treatment on all the heads in terms of work efficiency. On the other hand, the present inventors have recently been able to rest an animal in a standing position by pre-administering a sedative such as xylazine to a large animal, and it becomes possible to measure an auditory brainstem response. I found. That is, by pre-administering a sedative when measuring the auditory brainstem response, a stable auditory brainstem response can be obtained and the safety of the operator can be improved. In addition, when an animal sits down by a sedative treatment, measurement is possible even in that state.

  The sedative is not particularly limited, but xylazine is preferred. Although different depending on the individual, when xylazine is used, a predetermined effect can be obtained by intramuscular administration of about 0.05 mg / kg. After administration, the state of the individual may be observed, and additional administration may be performed depending on the situation.

  Wear earphones for sound stimulation on the left and right ears of animals. The size, shape, etc. of the earphone are not particularly limited, but those having a structure that closely contacts the ear canal of the animal are preferable. As a result, the stimulating sound pressure can be reliably sent to the tympanic membrane of the animal and external noise can be blocked, so that stable auditory brainstem response waveform data can be obtained without using a special laboratory (shield room). Can be obtained.

  When measuring the auditory brainstem response, it is desirable to hold both ears of the animal in advance. Thereby, since the noise derived from the electromyogram by moving the ear can be prevented, stable waveform data can be derived. For ear retention, the animal ear retention device according to the present invention described later can be used.

  An electrode is attached to the head of the test animal. The electrode mounting site is not particularly limited as long as the evoked potential derived from the brainstem can be detected. For example, by attaching the lead electrode (plus) to the top of the head, the reference electrode (minus) to the middle part of the orbit and the ear root, and the ground electrode (earth) to the middle part of both eyes and the nose Simple waveform can be acquired. Attach the reference electrodes to the left and right.

  The auditory brainstem reaction measuring device itself may be any device that can output a predetermined sound stimulus and can detect an evoked potential, and can also measure a device developed for humans.

  The type, size, frequency, and the like of the sound stimulus can be set as appropriate and are not particularly limited. For example, with a click sound, the stimulation sound pressure is about 75 to 120 dBnHL (“decibel normalized hearing level”, the same applies hereinafter), the stimulation frequency is 10 to 30 times / second, and the stimulation duration is 0.1 to 0.2 milliseconds. By adding these stimuli 500 to 2,000 times, the waveform of the auditory brainstem response can be obtained.

<Brain stem dysfunction detection method according to the present invention>
In the brainstem dysfunction detection method according to the present invention, waveform data of an auditory brainstem response is acquired from a sedated animal, and based on the data, the affliction of a specific brainstem dysfunction is detected.

  For example, based on the waveform data of the auditory brainstem response in a normal individual or an individual affected by a specific brainstem dysfunction as a reference, the waveform data of the auditory brainstem response newly obtained from the animal to be examined is compared with the reference data to identify Detecting brainstem dysfunction.

  FIG. 1 is waveform data of an auditory brainstem response in a normal individual of an adult cow.

  This data is waveform data of an auditory brainstem reaction measured by administering 0.05 mg / kg intramuscularly of xylazine to an adult Holstein cow and holding the cow under standing and sedation. Click sound is used for the sound stimulus, the stimulus frequency is 10 Hz, the stimulus duration is 0.1 millisecond, and these stimuli are data obtained by adding 2,000 times.

  In the figure, the horizontal axis represents the time after applying the sound stimulus (Latency; latency, unit milliseconds (msec)), and the vertical axis represents the evoked potential (Amplitude, added value, unit: μV). Each waveform in the figure is obtained when the stimulation sound pressure of the sound stimulation is set to 105, 95, 85, 75, and 65 dBnHL, respectively.

  As shown in FIG. 1, a waveform based on the auditory brainstem response appears at 75 dBnHL or more, and four clear positive waves are recognized within 5 milliseconds after the sound stimulation. In the figure, “I” is from the auditory nerve, “II” is from the medulla, “III” is from the bridge, and “V” is from the midbrain.

Regarding the waveforms in normal cattle, there is almost no difference in the waveform shape of the auditory brainstem response between varieties, for example, between Holstein and Kuroma, but the latency (peak) and interwave latency of each waveform There is a difference in time (IPL (inter peak latency); time between peaks, hereinafter the same) (see Tables 1 and 2). Therefore, the waveform data of the auditory brainstem response in normal individuals may be set for each breed. In addition, in normal cattle, there is almost no waveform difference due to age.

  On the other hand, specific auditory brainstem dysfunction waveform data is obtained for specific brainstem dysfunction.

  For example, in the case of a cow suffering from BSE, the waveform data of the auditory brainstem response has a prolonged III-wave and V-wave latency in both left and right sides. The extension of the latency starts before the appearance of the neurological symptoms of BSE, and the degree of the extension increases irreversibly with the onset of the neurological symptoms.

  In the case of BSE-affected cattle, the latency between I waves and V waves (interwave latency) is significantly prolonged. When the stimulation sound pressure is 105 dBnHL and the inter-wave latency between I and V is extended by 3.3 msec or more to the left and right sides, there is a high possibility of suffering from BSE.

  In addition, in BSE-affected cattle, all potentials from I wave to V wave decrease with the progress of symptoms. In cattle with BSE showing neurological symptoms such as “tremor”, the waveform disappears at 95 or 85 dBnHL or less.

  Therefore, by using the waveform data of the auditory brainstem response in a normal individual as a reference, the measurement data of the auditory brainstem response newly obtained from the animal to be examined is compared with the reference data, and the above features are detected, so that BSE Can be detected.

  Further, based on the waveform data of an auditory brainstem response in an individual affected with BSE, the measurement of the auditory brainstem response newly obtained from the animal to be examined may be compared with the reference data to detect BSE disease. .

  In addition, when the auditory brainstem response was measured for cattle suffering from ruminal displacement and ketosis, there was no significant difference in waveform from that in normal individuals. Therefore, the brainstem dysfunction can be differentiated from those diseases by using the brainstem dysfunction detection method according to the present invention.

<Brain stem dysfunction detection program according to the present invention>
The above-described brainstem dysfunction detection method can be automated to detect and determine the presence or absence of brainstem dysfunction by being programmed and implemented on a computer.

  FIG. 2 is an example of a flowchart of a brainstem dysfunction detection program according to the present invention.

  This program includes a step of acquiring waveform data of an auditory brainstem response obtained from a sedated animal (reference S1), and previously acquired reference data of an auditory brainstem response in a normal individual and / or an individual suffering from brainstem dysfunction And at least a step of detecting brain stem dysfunction (reference S3) based on a difference between the waveform data and the auditory brainstem response reference data.

  The waveform data of the auditory brainstem response obtained by the above-described method for acquiring the auditory brainstem response is transferred to a memory, and the auditory brainstem response reference data in a normal individual and / or an individual suffering from brainstem dysfunction is transferred from a storage medium to the memory. By calculating the difference between the two data, the presence or absence of brainstem dysfunction can be automatically detected and determined.

<Audio brainstem reaction detection system (or apparatus) according to the present invention>
An auditory brainstem reaction detection system (or apparatus) according to the present invention includes sound stimulation generating means for generating sound at a predetermined sound pressure level and predetermined intervals, an electrode attached to an animal and acquiring an auditory brainstem reaction. And a control unit and a portable computer functioning as a power source.

  As described above, in this system (apparatus), by using a portable computer or the like as a power source, no power source or ground is required, and a power transformer or the like can be omitted from the configuration. For this reason, the entire system (device) can be made compact in size to the extent of an attache case and can be reduced in weight.

  Therefore, by using this system (apparatus), the auditory brainstem response can be measured easily, at low cost, with low labor, and at any location. This system (apparatus) can also be used to measure the auditory brainstem response in other industrial animals such as pigs, sheep and goats and pets such as dogs and cats.

  FIG. 3 is a diagram showing a configuration example of an auditory brainstem reaction detection system (apparatus) according to the present invention.

  The system (apparatus) in FIG. 3 mainly includes a computer unit A including a power source A1, an input unit A2, a display unit A3, a control unit A4, a storage unit A5, a memory A6, a sound stimulus generation unit B1, an amplifier B2, A sound stimulus generation means B including an earphone B3 and the like, and an auditory brainstem reaction acquisition means C including an electrode C1, a biological amplifier C2, an A / D converter C3, and the like.

  The power source A1 is used not only as the computer unit A but also as a power source for the sound stimulus generation unit B1, the biological amplifier C2, the A / D converter C3, and the like. Thereby, the structure of a system (apparatus) can be simplified.

  A DC power source such as a battery is used as the power source A1. As a result, no grounding is required, and a power transformer or the like can be omitted from the configuration. Therefore, the entire system (apparatus) can be downsized to the size of an attache case and can be reduced in weight. Note that a battery of a portable computer can also be used as the power source A1.

  The input means A2 performs setting / operation etc. via a keyboard or the like. The display unit A3 is a part that outputs setting information, operation information, processing result information, and the like, such as a display.

  The storage unit A5 includes a measurement data storage unit A51, a reference data storage unit A52, a calculation program storage unit A53, and the like.

  The measurement data storage unit A51 stores waveform data of evoked potentials acquired by the auditory brainstem reaction acquisition means C. On the other hand, the reference data storage unit A52 stores reference data of an auditory brainstem reaction acquired in advance for normal individuals and / or individuals with brainstem dysfunction. The arithmetic program storage unit A53 stores a brainstem dysfunction detection program.

  Then, after the measurement data, reference data, and program are transferred from the measurement data storage unit A51, the reference data storage unit A52, and the calculation program A53 to the memory A6, the control unit A4 performs calculation processing, and brainstem dysfunction Detection / determination is performed.

  The control unit A4 also controls other units. The control unit A4 is configured by a CPU or the like.

  The sound stimulus is generated at a predetermined sound pressure level and at predetermined intervals by the sound stimulus generator B1, amplified by the amplifier B2, and transmitted to the test subject animal via the earphone B3. Settings relating to sound stimulation can be performed by the input means A2, and the control of the sound stimulation generating unit B1 is performed by the control unit A4.

  As described above, the size, shape, and the like of the earphone B3 are not particularly limited, but a configuration that closely contacts the ear canal of the animal is preferable. The material of the earphone is not particularly limited as long as it can improve the sealing performance in the ear canal. For example, a silicone resin can be applied.

  On the other hand, the evoked potential of the auditory brainstem reaction generated by the sound stimulation is acquired from the electrode C1, amplified by the biological amplifier C2, changed to a digital signal by the A / D converter C3, and measured data via the control unit A4. It is stored in the storage part A51.

  The type of the electrode C1 is not particularly limited, but since an animal has body hair, the needle electrode is easier to use than the dish electrode. The needle electrode has a diameter suitable for each animal. For example, in the case of a cow, a cow with a diameter of 0.2 mm can be used. However, since a cow has a relatively thick skin at the part where the needle electrode is mounted, the needle may be bent or broken. Accordingly, it is advantageous to use a 0.35 mm (0.3 mm or more and 0.4 mm or less) needle except that it is difficult to bend and easy to wear, except for an individual who is sensitive to a needle stick.

  The material of the needle is not particularly limited, and a known material can be used. For example, stainless steel, silver-silver chloride, platinum alloy, and the like are applicable, and stainless steel is preferable in terms of hardness and price. Since the potential of the auditory brainstem reaction is weaker than that of an electroencephalogram or the like, the electrode resistance is desirably 5 kΩ or less.

  The needle of the electrode C1 may be configured to be detachable from the cord. Thereby, since the code can be used as it is and only the needle can be exchanged, the measurement cost can be reduced. Moreover, infection between test animals can be prevented by exchanging only the needle for each measurement.

<Ear restraint for animals according to the present invention>
As described above, in the measurement of the auditory brainstem response, it is possible to prevent the electromyogram-derived noise caused by moving the ears by holding both ears of the animal in advance, so that stable waveform data can be derived. .

  FIG. 4 is an external view showing an example of an animal ear retainer according to the present invention. In the figure, an arrow X represents the forward direction (head direction) when the animal ear restraint is worn.

  The animal ear restraint D according to the present invention includes a neck fixing part 1 that is wound around the neck of an animal and an ear fixing part 2 that fixes an animal ear.

  The cervical fixing part 1 is a substantially bilaterally symmetric belt-like member and is wound around the cervical part of an animal. When wound around the animal's neck, the inner surface 11 is in contact with the animal's skin, and the outer surface 12 is partially bonded to the ear fixing portion 2.

  About the winding fixing means of the neck fixing | fixed part 1, a well-known means can be employ | adopted and it does not specifically limit. In FIG. 4, the method of winding the neck fixing | fixed part 1 with the hook_and_loop | surface fastener formed in the back surface 31 of the connection part 3 is employ | adopted. That is, both end portions 12 ′, 12 ′ of the outer surface 12 of the cervical fixing portion 1 are formed by female portions of hook-and-loop fasteners, and the male portion and both-end vicinity portions 12 ′, 12 of the hook-and-loop fastener 31 formed on the connecting portion 3. Adopts a structure that is attached to and wrapped around the animal's neck.

  A predetermined substantially curved shape 14 may be formed on the front side of the neck fixing portion 1 in a symmetrical manner. In general, especially when holding large animals, the neck is held using a bow or rope. By forming the substantially curved shape 14, it is possible to wear the ear support D in a state where it does not overlap with the headline or the like.

  You may provide the head connection part 15 which connects a head, etc. in the predetermined position in the substantially curved shape 14 of the neck fixing | fixed part 1. FIG. By forming the substantially curved shape 14, the neck fixing portion 1 and the bow are in a substantially parallel position. Therefore, the accuracy of the ear restraint can be improved by providing the head-to-head communication portion 15 and connecting the head-to-head communication to the neck fixing portion 1.

  The configuration of the headline communication unit 15 is not particularly limited. In FIG. 4, the method which comprises the head-and-teeth communication part 15 with a hook_and_loop | surface fastener is employ | adopted. That is, a female portion of a hook-and-loop fastener is formed at predetermined positions on the inner side surface 11 and the outer side surface 12 of the neck fixing portion 1, and the male portion 15 of the hook-and-loop fastener is bonded to the portion in a folded state, and the inside thereof is entangled. The structure which passes is adopted.

  On the other hand, the ear fixing part 2 is also a substantially symmetrical belt-like member, and is a part for fixing the animal's ear, and is connected in the vicinity of the midline 12 ″ of the outer surface 12 of the neck fixing part 1.

  In FIG. 4, a female part of a hook-and-loop fastener is formed on a portion of the outer surface 12 of the neck fixing part 1 that is in contact with the ear fixing part 2, and an inner side surface 21 of the ear fixing part 2 is formed by a male part of the hook-and-loop fastener. Yes.

  And after mounting | wearing the neck fixing | fixed part 1, a hook-and-loop fastener is adhere | attached in the state which pinched | interposed the ear of the animal between the cervical fixing | fixed part 1 and the ear fixing | fixed part 2 respectively on right and left, and an ear is fixed. Thereby, since the movement of the ear can be stopped almost completely, noise derived from the electromyogram caused by moving the ear can be prevented.

  About the material of the neck fixing | fixed part 1 and the ear | tip fixing | fixed part 2, well-known things, such as a skin member and a synthetic resin member, can be employ | adopted and it does not specifically limit. About the ear | tip fixing | fixed part 2, you may form a part with a transparent member. Thereby, it becomes possible to confirm the wearing state of the earphone from the outside.

  FIG. 5 is a schematic view showing a state in which the ear holder D according to the present invention is mounted. FIG. 5A shows a state before the ear holder is attached, FIG. 5B shows a state in which the neck fixing portion 1 is wound, and FIG. 5C shows a state when the ear holder is attached. Although FIG. 5 illustrates a cow as an example, the present invention is not limited thereto.

  First, the head 4 is attached to the head of the animal (FIG. 5A), and then the neck fixing portion 1 is wrapped around the animal neck with the head 4 and the substantially curved shape 14 being substantially parallel. (FIG. 5B). Then, the head 3 and the neck fixing portion 1 are communicated with each other through the head communication portion 15 (FIG. 5B). Next, with the earphone attached to the ear, the ear is sandwiched between the neck fixing portion 1 and the ear fixing portion 2 to hold the ear (FIG. 5C). Thereby, since the noise derived from the electromyogram by moving the ear can be prevented, stable waveform data can be derived.

  In this example, the auditory brainstem response of BSE-affected cattle was measured.

  Experimental BSE-affected cattle were prepared by administering 1 mL of 10% brain emulsion of BSE-affected cattle into the brain of healthy Holstein cattle (2-4 months old, n = 11). As a negative control, three cattle inoculated into the brain with 1 mL of 10% brain emulsion of healthy Holstein cattle were prepared. Auditory brainstem responses were measured at 12, 14, 20, 22, and 24 months after intracerebral inoculation.

  For the measurement of the auditory brainstem reaction, “Neuropack MEB-9100 (manufactured by Nihon Kohden Co., Ltd.)” was used. The auditory brainstem reaction was measured by administering 0.05 mg / kg intramuscularly of xylazine and holding the cows in a standing / sedated state. A click sound was used as the sound stimulus, the stimulus frequency was 10 Hz, the stimulus duration was 0.1 milliseconds, and these stimuli were acquired by adding 2,000 times.

  Earphones for sound stimulation were attached to the left and right ears of the animals, respectively. The earphones were newly made with a silicone resin and used in close contact with the ear canal.

  The lead electrode (plus) was attached to the top of the head, the reference electrode (minus) was attached to the middle part of the orbit and the ear root, and the ground electrode (earth) was attached to the middle part of both eyes and the nose. A needle electrode having a diameter of 0.22 mm was used as the electrode.

  The results are shown in FIG. 6, FIG. 7, and FIG.

  FIG. 6 shows waveform data of the auditory brainstem response after 20 months and 24 months after prion inoculation. FIG. 7 is a graph showing the transition of the latency and interwave latency of the auditory brainstem response after prion inoculation. Shows the waveform data of the auditory brainstem response of BSE-affected cattle 22 months after prion inoculation in the brain.

  In FIG. 6, the left graph shows the measurement data of the BSE-affected cow, and the right graph shows the measurement data of the negative control cow. The horizontal axis represents the time after applying the sound stimulus (Latency; latency, unit milliseconds (msec)), and the vertical axis represents the obtained evoked potential (added value, unit: μV). “20 months after inoculation” represents waveform data 20 months after inoculation in the prion brain, and “24 months after inoculation” represents waveform data 24 months after inoculation in the prion brain. “Left stim.” Represents the measurement data of the left evoked potential, and “Right stim.” Represents the measurement data of the right evoked potential.

In FIG. 7, “Wave I”, “Wave II”, “Wave
"III" and "Wave V" are the I wave (derived from the auditory nerve), II wave (derived from the medulla oblong), III wave (derived from the bridge), and V wave (derived from the midbrain) (Peak latency (msec)), respectively. To express. "I-III IPL", "III-V IPL", and "IV IPL" are the interpeak latency (msec) between I wave and III wave, III wave and V wave, and I wave and V wave, respectively. )). The four bar graphs in each graph are, from the left, measurement data of the left evoked potential in BSE-affected cattle, measurement data of the left evoked potential in normal cattle, measurement data of the right evoked potential in BSE-affected cattle, The measurement data of the right evoked potential in a negative control cow are represented. The five groups in each graph represent evoked potential measurement data at 12, 14, 20, 22, and 24 months after prion inoculation from the left, respectively.

  In FIG. 8, the horizontal axis of each graph represents the time after applying a sound stimulus (Latency; latency, unit milliseconds (msec)), and the vertical axis represents the obtained evoked potential (added value, unit: μV). , Respectively. Each waveform is obtained when the stimulation sound pressure of sound stimulation is set to 105, 95, 85, 75, and 65 dBnHL, respectively.

  As shown in FIG. 6, in the case of a cattle with BSE, the waveform data of the auditory brainstem response has extended latency of III wave and V wave to both left and right sides. The extension of this latency started before the appearance of neurological symptoms of BSE, and the degree of the extension irreversibly increased with the onset of neurological symptoms.

  Further, as shown in FIG. 7, in the case of BSE-affected cattle, the latency between I-waves and V-waves (inter-wave latency) was significantly extended. This result indicates that, when the stimulation sound pressure is 105 dBnHL and the wave latency between I and V is extended to the left and right sides by 3.3 msec or more, the suspicion of suffering from BSE is high.

  Further, as shown in FIG. 8, in the BSE-affected cattle, all potentials from I to V waves decreased with the progress of symptoms. In particular, in BSE-affected cows showing neurological symptoms such as “tremor”, the waveform disappeared at 95 or 85 dBnHL or less.

  As described above, according to this example, it was found that the measurement data of the auditory brainstem response in the BSE-affected cow is different from that in the negative control cow. This result is based on the waveform data of the auditory brainstem response in normal individuals or individuals with BSE, and the above characteristics are detected by comparing the measured data of the auditory brainstem response newly obtained from the animal to be examined with the reference data. This shows that BSE morbidity can be detected.

  In Example 2, it was verified whether there was an influence of stress by measuring the auditory brainstem response according to the present invention.

  For holstein species (n = 22) and Japanese black species (n = 10), cortisol concentrations in urine and saliva were measured before and after the measurement of the auditory brainstem reaction.

The results are shown in Tables 3 and 4. Table 2 shows the results for Holstein, and Table 3 shows the results for Japanese black.

  As shown in Tables 3 and 4, in both varieties, the cortisol concentration was low both before and after the measurement. This result shows that the test of the auditory brainstem reaction with sedation is less stressed, and that it is suitable as a clinical test for cattle considering that the test data is stabilized by sedation.

  In Example 3, whether the measurement data of the equivalent auditory brainstem response can be obtained even when a large animal needle electrode (diameter 0.35 mm) is used instead of the existing needle electrode (diameter 0.2 mm) Verified.

  The measurement of the auditory brainstem reaction was generally performed by the same method as in Example 1. As a test animal, a normal Holstein species was used. A needle electrode having a diameter of 0.35 mm and made of stainless steel was used. Further, the needle electrode used was a cord and needle that were detachable. The stimulation sound pressure was set to 105 dBnHL, and the data was acquired by adding 2,000 times.

  The results are shown in FIG. FIG. 9 shows waveform data of an auditory brainstem reaction when an existing needle electrode and a large animal needle electrode are used. In the figure, the horizontal axis represents the time after applying the sound stimulus (Latency; latency, unit milliseconds (msec)), and the vertical axis represents the obtained evoked potential (added value, unit: μV).

  As shown in FIG. 9, there was almost no change in the waveform data of the auditory brainstem reaction between the case of using an existing needle electrode and the case of using a large animal needle electrode. This result shows that, in the case of a large animal, equivalent waveform data can be obtained even if a large diameter is used for the needle electrode.

Waveform data of auditory brainstem response in normal adult cattle. The flowchart of the brain stem dysfunction detection program which concerns on this invention. The figure which shows the structural example of the auditory brainstem reaction detection system (or apparatus) which concerns on this invention. The external view which shows the example of the ear | edge holder for animals which concerns on this invention. The schematic diagram which shows the state before mounting | wearing the ear holder D which concerns on this invention. The schematic diagram which shows the state which wound the neck fixing | fixed part 1 of the ear | edge holder D concerning this invention. The schematic diagram which shows the state which mounted | wore with the ear holder D which concerns on this invention. Waveform data of auditory brainstem responses at 20 months and 24 months after prion inoculation. The graph which shows transition of the latency of an auditory brainstem reaction after prion intracerebral inoculation, and wave latency. Waveform data of the auditory brainstem response of BSE-affected cattle 22 months after prion inoculation. Waveform data of auditory brainstem response when using existing needle electrodes and needle electrodes for large animals.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Neck part fixing part 11 Inner side surface of neck fixing part 1 12 Outer side surface of neck fixing part 1 Ear fixing part 3 Connection part 4 Headline A Computer A1 Power supply A2 Input means A3 Display part A4 Control part A5 Storage part A51 Measurement data storage A52 Reference data storage unit A53 Operation program storage unit A6 Memory B Sound stimulus generation means B1 Sound stimulus generation part B2 Amplifier B3 Earphone C Auditory brainstem reaction acquisition means C1 Electrode C2 Bioamplifier C3 A / D converter

Claims (3)

Acquired auditory brainstem response waveform data from sedated large animals,
A BSE morbidity detection method for detecting morbidity of BSE by detecting the left and right bilateral extension of the latency of III wave and V wave in the waveform data . Obtaining waveform data of an auditory brainstem response obtained from a sedated large animal;
Obtaining auditory brainstem response reference data in a normal individual and / or an individual suffering from brainstem dysfunction acquired in advance;
Based on the difference between the measurement data and the auditory brainstem response reference data , detecting the extension of left and right bilaterality in the latency of III wave and V wave ;
A BSE disease detection program for causing a computer to execute a process including at least A system for detecting sedation of a large animal with BSE , comprising:
Sound stimulation generating means for generating sound at a predetermined sound pressure level and a predetermined interval;
An electrode for attaching to the large animal and acquiring an auditory brainstem reaction;
At least a control unit and a portable computer that functions as a power source,
A BSE morbidity detection system that acquires BSE morbidity by acquiring waveform data of the auditory brainstem response from the large animal, and detecting a left-right bilateral extension of III wave and V wave latencies in the waveform data.