RU2652733C1 - Method of adjusting the speech processor of the cochlear implant system - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to surdology. Record auditory responses of the brain to stimulation by constant modulated stimuli simultaneously at frequencies of 500, 1,000, 2,000 and 4,000 Hz at a stimulus intensity of 60 dB and a modulating frequency of 40 Hz in waking state or 90 Hz in sleep state. If response is received, the setting is considered optimal for the corresponding frequency. If there is no response, the intensity of stimulation for a given frequency is increased until a response is obtained. Then, the stimulus is repeated against a background of masking noise, and in the absence of an answer, the stimulation level is increased until a response is obtained.

EFFECT: method allows to increase the reliability of information about the dynamic range of sound perception in various acoustic conditions, which is achieved by the above-mentioned techniques of the proposed invention.

1 cl, 1 ex

Description

The invention relates to medicine, namely to audiology, otorhinolaryngology.

Cochlear implantation followed by auditory-speech rehabilitation is the most effective benefit for patients with severe sensorineural hearing loss and deafness [1]. Adequate tuning of the processor of the cochlear implantation system allows the patient to perceive sound (including speech) information, which allows him to be integrated into the hearing environment.

CPU tuning in young children based on behavioral techniques (depending on the response to the stimulus) is often difficult due to undeveloped communication skills, including in children with combined neurological pathology. In this regard, the use of objective methods based on the registration of electrophysiological responses of various parts of the auditory analyzer has become widespread. Among such techniques, the most informative in terms of correlation with thresholds of maximum comfort (the most critical setting) is considered to be the registration method of the threshold of an electrically induced stapedial reflex (ESRT - Evoked Stapedial Reflex Threshold) [2]. The method consists in gradually increasing the level of stimulation of the auditory nerve until the onset of reflex contraction of the stirrup muscle (unconditioned reflex of the auditory analyzer to excessive acoustic stimulation). This testing procedure can be carried out on all channels of the implant to obtain a threshold configuration of the maximum stimulation level [3].

There is also a method for objectively determining thresholds for sound perception by recording evoked auditory responses of the brain to a constant modulated tone - auditory steady-state response (ASSR test). The principle of the method consists in extracting from the electroencephalographic signal and recording responses of the brain to constant sinusoidal stimuli applied at the main speech frequencies (using a specialized algorithm that is preinstalled in the recording system of auditory potentials of the brain) [4].

The closest solution is the "Method for determining the optimal parameters of hearing aid", Patent No. 2414168 of 03/29/2010, and we take it as a prototype. The method is performed by registering ASSR thresholds (ASSR test) in a patient with a hearing aid installed and configured. In conditions of physiological sleep (to reduce the electroencephalographic activity of the brain), a head phone is set up, calibrated taking into account the microphone of the hearing aid. Next, the auditory response of the brain to a constant modulated tone (ASSR) is recorded at a stimulus intensity of 60 dB. Upon receipt of a positive response, the setting is considered optimal; in the case of a negative response during the study, a change in the parameters is carried out.

The above methods have their drawbacks, namely:

For the method of recording the reflex threshold for all channels, these are:

1) the impossibility of applying the method in the first three months of using the implant;

2) stimulation at maximum comfort values causes subjectively unpleasant (up to pain) sensations in patients, which can lead to refusal to use the system by young children;

3) the inability to perform the method in the presence of inflammation or pathological changes in the middle ear (absence or limitation of stapedi muscle mobility).

For a method for determining the optimal parameters of hearing aids, these are:

1) the need for the patient to be in a state of natural physiological sleep during the study;

2) the impossibility of obtaining objective data on the dynamic range of sound perception - the onset of acoustic discomfort from excessive sound stimulation;

3) mandatory waiting for the end of the test to change the settings with the subsequent repetition of the study with updated parameters;

4) the factor of “noisy” acoustic situation is not taken into account.

To eliminate the disadvantages of the above clinical methods, we have proposed a method for tuning the speech processor of a cochlear implantation system.

The purpose of the invention is the obtaining of objective data on the possibility of sound perception by a patient with a cochlear implant (s) installed in various acoustic situations.

The method consists in the following: a patient with an installed cochlear implantation system is seated in a chair (or laid on a couch for young children) with an acoustic loudspeaker installed at a distance of 1 meter from the processor (processors, if the patient has implants installed on both sides). The device for recording auditory potentials is the Neuro-Audio system, manufactured by Neurosoft (Russia). Electrodes are fixed on the patient’s head according to the scheme of the method for recording auditory evoked brain potentials. The auditory responses of the brain to constant modulated tones are recorded simultaneously at frequencies of 500, 1000, 2000 and 4000 Hertz (Hz) with a stimulus intensity of 60 decibels (dB). The study is carried out at a modulating frequency of the stimulus of 40 Hz, which allows you to record the response in the wakeful state (or 90 Hz, if the patient is in a state of sleep). If there is an answer (the algorithm registers automatically), the setting is considered optimal for the corresponding frequency. In the absence of an answer, the level of stimulation at the electrodes of the corresponding frequency group is increased; since the progression of the response occurs in real time, an increase in the level of stimulation is possible during the test. Then, the stimulus is repeated against the background of masking noise (imitation of a noisy environment). If there is no response, the stimulation level of the respective implant channels is increased until a response is received (ASSR threshold is recorded).

Positive effect: the possibility of using the method without contraindications, the possibility of conducting research in early childhood, improving the quality of auditory-speech rehabilitation, the appearance of additional data on tuning speech processors, including in patients with bilateral installation of implants (bilateral cochlear implantation) in various acoustic situations (sound perception sound perception in noise).

Concrete example

Extract from the outpatient card of patient B.V., 7 years old. Diagnosis: sensorineural hearing loss, grade IV (deafness). Condition after cochlear implantation on both sides.

The child is a user of cochlear implantation systems with three years of experience. According to the parents, in a noisy environment (street, many sound sources), the child ceased to perceive addressed speech. Carrying out ASSR registration in a free sound field (with processors installed and turned on) made it possible to register responses at 60 dB, but no responses were recorded when masking noise was added. Further correction of the stimulation parameters to the level at which the ASSR response was obtained under masking conditions made it possible to create a new listening program, using which the speech intelligibility of the patient improved in various acoustic situations.

Information sources

1. Anderson S.A., Lazard DS, Hartley DE Plasticity in bilateral superior temporal cortex: Effects of deafness and cochlear implantation on auditory and visual speech processing. Hear Res . 2017; 343: 138-49. doi: 10.1016 / j.heares.2016.07.07.013

2. Raghunandhan S., Ravikumar A., Kameswaran M., Mandke K., Ranjith R. A clinical study of electrophysiological correlates of behavioural comfort levels in cochlear implantees. Cochlear Implants International . 2014; 15 (3): 145-60. DOI: 10.1179 / 1754762814Y.0000000064 / PMID: 24606544

3. Daikhes HA, Pashkov A.V., Petrov S.M., Yanov Yu.K. A modified method of recording the stapedial reflex in implanted patients when tuning the speech processor. Russian otorhinolaryngology . 2007; 3: 19-21.

4. Vander Werff KR, Brown C. J., Gienapp B. A., Schmidt KM Comparison of Auditory Steady-State Response and Auditory Brainstem Response Thresholds in Children. J. Am. Acad. Audiol. 2002; 13: 227-35.

Claims (1)

A method for tuning the speech processor of a cochlear implant system in patients with cochlear implants, including recording the auditory responses of the brain to stimulation by constant modulated stimuli simultaneously at frequencies of 500, 1000, 2000 and 4000 Hz, characterized in that data on the perception of sound through the implant processor at the indicated frequencies are carried out with a stimulus intensity of 60 dB and a modulating frequency of 40 Hz in the wakeful state or 90 Hz in the sleep state, upon receipt of a response, the setting is considered optimal for Enikeev frequency response in the absence of stimulation intensity is increased for a given frequency until a response is then repeated feeding stimuli for background masking noise, and if no response to the stimulation level is increased until the response is received.