A quick method for determining the relative minimum audible distance using sound images.

Auditory localization plays an essential role in various tasks, including spatial orientation, locomotion, attention and memory. Optimization of experimental routine is important for preliminary assessment of the subject's sound localization ability. In the present study, a new quick technique for estimating the relative minimum audible distance (RMAD) using sound images is introduced. Twenty adults with normal hearing took part in six RMAD measurements in free field. The reference RMAD values were obtained using a method of constant stimuli by physically positioning a real sound source. The same method was used with stationary sound images created by superposition of signals emitted by two loudspeakers. To optimize the measurements, the RMADs were determined for the sound images using two adaptive psychoacoustic procedures known as one-down, one-up and two-down, one-up staircases. The group-average RMADs obtained by the method of constant stimuli for both types of stimuli and by two adaptive procedures were similar, 7% (SD = 2%). The effect of whether subjects were sighted or blindfolded was not significant for measurements of RMAD to sound images. The average measurement times were 373 s (SD = 20 s) for the method of constant stimuli, 85 s (SD = 9 s) for the one-down, one-up, and 124 s (SD = 14 s) for the two-down, one-up procedure. The results are consistent with the previous studies and confirm the validity of the measurements of RMAD using adaptive procedures with stationary sound images as a quick method.

[Rare observation of petrositis complicated by parapharyngeal abscess in an 8-year-old patient]. / Redkoe nablyudenie petrozita, oslozhnennogo parafaringeal'nym abstsessom, u patsienta 8 let.

A clinical case of diagnosis and treatment of an 8-year-old patient with bilateral acute suppurative otitis media (ASOM) complicated by left mastoiditis and petrositis is presented. By itself, such a rare complication of ASOM as petrositis manifested itself not in the form of the classic Gradenigo triad, but as a parapharyngeal abscess (PPA), due to the destruction of the lower wall of the temporal bone pyramid. Complications arose as a result of contact and hematogenous pathways for the spread of the infection, which debuted in the middle ear cavities 1 month before the patient was admitted to the hospital. The combination of factors such as an aggressive pathogen, the anatomical structure of the middle ear, a decrease in the immune reactivity of the child's body, the spread of infection through the lower cells of the temporal bone pyramid and the lack of timely antibiotic therapy, led to destructive changes in the bony walls of the temporal bone and the spread of a purulent process to the temporal pyramid bones, and then to the parapharyngeal space. The destruction by inflammation of the lower wall of the pyramid of the temporal bone led to the development of PPA, and not meningoencephalitis, which could have fatal consequences.

[Comparative cytological analysis of the middle ear exudate in different children's groups]. / Sravnitel'nyi tsitologicheskii analiz ekssudata srednego ukha u raznykh detskikh grupp.

The purpose: to compare the types of cytograms of exudate from the middle ear between patients with exudative otitis media (EOM) with congenital clefts of the lip/palate (CCLP) and without CCLP, determining the stages of chronic disease and the significance of surgery on the middle ear. PATIENTS AND METHODS: Two clinics was parallel conducted a cytological examination of exudate of the middle ear in children. The first group consisted of 30 patients aged 2 to 17 years with EOM without CCLP (n=54 ears). The 2nd group included 17 patients aged 1 year 4 months to 10 years with EOM with CCLP (n=34 ears). RESULTS: In the 1st group, in 61% of cases (n=33), an inflammatory-regenerative type of cytogram was detected, in 39% (n=21) - a regenerative, inflammatory type of cytogram was not detected. In the 2nd group, in 82.4% of cases (n=28), an inflammatory type of cytogram was observed, in 14.7% (n=5) - an inflammatory-regenerative type, in 2.9% (n=1 ear) - a regenerative type. CONCLUSION: With CCLP, the inflammatory nature of the cytogram of the resulting exudate from the middle ear is more common, which is characterized by signs of destruction of the mucous membrane, decay and degradation of the basal and cell membranes. Patients with CCLP often suffer from EOM. They are more likely to development of chronic purulent otitis media, including with cholesteatoma. Destructive changes in the mucous membrane of the middle ear are found in children of different ages. Taking into account the analysis of cytograms of the exudate of the middle ear with CCLP, the imposition of long-term ventilation tubes is justified.

Differences in the Postural Responses to Approaching and Receding Sound Images in Subjects with Different Perceptual Styles.

A hypothesis on the universal character of perceptual style for analyzing the surrounding space during sensory interactions has been tested. The indices of postural responses to moving and stationary auditory images in the groups of field-dependent and field-independent subjects, i.e., those who perceive spatial information about the object considering or ignoring the background, respectively, have been investigated. The differences in the sway parameters in both groups were revealed only in the case of moving auditory images. Body sway was more prominent in the group of field-independent subjects, whereas in the subjects from the field-dependent group, backward body displacement was observed during listening to approaching auditory images. Therefore, the perceptual style is reflected in the vertical postural responses to auditory information about the motion in the acoustic space.

[THE EFFECTS AND AFTEREFFECTS OF A SOUND SOURCE APPROACHING AND WITHDRAWING ON POSTURAL RESPONSES IN HUMANS ].

The multimodal influence of the auditory motion adaptation was studied until now on visual perception only, however, the auditory motion adaptation can influence other modalities. This study is the first attempt to investigate postural aftereffects to 45-second adaptation to approaching or withdrawing sound images, that were simulated by rhythmic sequences of tone pulses changed linearly in amplitude and frequency in the free field. The oscillations of the center of pressure in the sagittal plane with the rhythm of stimuli were detected. These oscillations were more noticeable for approaching than for withdrawing stimuli and resulted in an increase of the length of the trajectory of the center of pressure and average linear velocity of its motion. The center of pressure shifted in the direction of the sound motion during listening to approaching sound images, and to the opposite direction during 20 s after its turning off. The shift to the opposite direction demonstrates typical negative aftereffect. The data are in accordance with the results of studies of postural responses to moving visual stimuli, where the «negative¼ effect was also revealed.

[MOTION AFTEREFFECT AS A UNIVERSAL PHENOMENON FOR SENSORY SYSTEMS INVOLVED IN SPATIAL ORIENTATION. III. AFTEREFFECT ARISING AFTER ADAPTATION TO MOTION IN SOMATOSENSORY AND VESTIBULAR SYSTEMS].

Motion aftereffect can be regarded as a consequence of self-motion illusions and lag effect of the sensory performance. Numerous experimental facts provide evidence of common mechanisms of motion aftereffect in various modalities based on conception of motion detectors. At present here are serious rea- sons to suppose that motion aftereffect is a characteristic feature of all sensory systems involved in spatial orientation, adaptation to motion in one sensory system results in a change of performance of another one and that such adaptation has an important adjusting significance for orientation of a moving organism. This review deals with argumentation of these conceptions.

[AUDITORY AFTEREFFECT OF CONTINUOUSEY AND BROKENLY APPROACHING SOUND IMAGES].

The auditory after effect of continuously and brokenly approaching sound images was investigated. The images were formed by sequences of broadband noise pulses, which were linearly modulated by their amplitude. These sequences were presented through two loudspeakers, placed at a distance of 1.1 and 4.5 m from a subject. Adaptation to continuous motion caused changes in perception of continuously moving sound sources, and adaptation to broken motion induced changes in perception of brokenly moving sources. Aftereffect didn't arise when adapting and test stimuli had different qualities of motion. Regardless to the quality of motion (broken or continuous) when adapting and test stimuli had same rhythmical structure aftereffect was stronger than when the stimuli had different structures. The results allow us to assume that the ways of processing information about continuously and brokenly moving sound sources are different.

[MOTION AFTEREFFECT AS A UNIVERSAL PHENOMENON IN SENSORY SYSTEMS INVOLVED IN SPACE ORIENTATION. II. AUDITORY MOTION AFTEREFFECT].

Adaptation to sound source motion can cause noticeable changes in spatial perception of the following sound stimuli. Neural mechanisms of selective sensitivity to motion are the basis of this phenomenon, called the auditory motion aftereffect. The auditory motion aftereffects were demonstrated under different stimulation conditions, both after the presentation of different motion models and in the real sound source motion. The auditory aftereffects are specifically characterized by its spatial and frequency selectivity as well as by the optimal motion velocity at which the effect is maximal. These features and the presence of the intersensory motion adaptation effects indicate a common nature of the auditory and visual motion aftereffects and allow suggesting the existence of the common system of motion adaptation for different modalities that provide spatial orientation.

[Thresholds of continuously approaching sound sources with rhythmic structures typical for biologically significant signals].

Localization of biologically significant moving rhythmic sources with different pulse/pause ratio has been practically not investigated. The issue of the perception thresholds of continuously approaching sound sources is addressed in the present study. The illusion of approaching sound courses was created by noise pulse sequences linearly increasing in amplitude and emitted by a loudspeaker placed at the level of the subject's head, 1.1 m away, under free field conditions. The sequences were formed by short (5 and 10 ms) or long (70 and 100 ms) pulses. The continuous movement thresholds were evaluated by the pauses between noise pulses varying from 10 to 150 ms. For the short pulse sequences the thresholds were 49 and 41 ms, while for the long ones they decreased to 21 and 16 ms, respectively. A progressive decay of the continuous movement perception threshold in pausing between noise pulses with increasing width over the whole pulse-width range studied was observed. The thresholds for the short noise pulse sequences were 54 and 51 ms did not differ significantly, while for the long noise pulse sequences they were almost twice as long, 91 and 115 ms. For the structures representing the short (up to 10 ms) pulse sequences, the thresholds were highly variable in magnitude that is indicative of a probabilistic evaluation of movement in case of insufficient information. For the long (tens of ms) pulse sequences, the threshold evaluation was stabilized. The continuous movement thresholds and the effective masking time for sound pulse sequences coincided suggesting critical role of non-simultaneous masking for the evaluation of movement continuity.

[Motion aftereffect as a universal phenomenon for sensory systems involved in orientation in space. I. Visual aftereffects].

At present there are serious grounds to believe that motion aftereffect is characteristic for all sensory systems involved in spatial orientation, and that adaptation to movement in one sensory system causes changes in another one and that such adjustment is of critical adaptive significance. In this part of the review there are briefly presented developments and the current state of studies on this issue in visual modality. The visual motion aftereffect has been studied considerably more completely as compared with other modalities. The main concepts about mechanisms of this phenomenon and employment of adaptation to motion in studies of visual analysis of movement at its different levels are actively used in the current scientific literature to understand mechanisms of this phenomenon in other sensory systems. The leading role of vision for orientation in space is manifested in the multimodal interaction where visual adaptation to movement produces significant changes of perception in other modalities.

[Peculiar features of mastoiditis in a brest-fed infant with the "exposed" facial nerve].

This paper reports the clinical case of mastoiditis in a 5-month old child in whom an unusual localization of the totally "naked" facial nerve outside of the bone canal in the mastoid part was discovered intraoperatively. This finding was quite unexpected because nerves are not visible on CT scanograms. The author emphasizes that the clinical course of otitis media in the breast- fed infants and young children is characterized by a number of peculiarities due to specific anatomical, physiological, and immunological features of the child's organism. She also notes that the number of antromastoidotomies for the treatment of mastoiditis has increased in Tatarstan during the recent years.

[Auditory aftereffects with approaching and withdrawing sound sources: dependence on trajectory and domain of presentation of adapting stimuli].

The perceptual peculiarities of sound source withdrawing and approaching and their influence on auditory aftereffects were studied in the free field. The radial movement of the auditory adapting stimuli was imitated by two methods: (1) by oppositely directed simultaneous amplitude change of the wideband signals at two loudspeakers placed at 1.1 and 4.5 m from a listener; (2) by an increase or a decrease of the wideband noise amplitude of the impulses at one of the loudspeakers--whether close or distant. The radial auditory movement of test stimuli was imitated by using the first method of imitation of adapting stimuli movement. Nine listeners estimated the direction of test stimuli movement without adaptation (control) and after adaptation. Adapting stimuli were stationary, slowly moving with sound level variation of 2 dB and rapidly moving with variation of 12 dB. The percentage of "withdrawing" responses was used for psychometric curve construction. Three perceptual phenomena were found. The growing louder effect was shown in control series without adaptation. The effect was characterized by a decrease of the number of "withdrawing" responses and overestimation of test stimuli as approaching. The position-dependent aftereffects were noticed after adaptation to the stationary and slowly moving sound stimuli. The aftereffect was manifested as an increase of the number of "withdrawing" responses and overestimation of test stimuli as withdrawal. The effect was reduced with increase of the distance between the listener and the loudspeaker. Movement aftereffects were revealed after adaptation to the rapidly moving stimuli. Aftereffects were direction-dependent: the number of "withdrawal" responses after adaptation to approach increased, whereas after adaptation to withdrawal it decreased relative to control. The movement aftereffects were more pronounced at imitation of movement of adapting stimuli by the first method. In this case the listener could determine the starting and the finishing points of movement trajectory. Interaction of movement aftereffects with the growing louder effect was absent in all ways of presentation of adapting stimuli. With increase of distance to the source of adapting stimuli, there was observed a tendency for a decrease of aftereffect of approach and for an increase of aftereffect of withdrawal.

[Auditory approach and withdrawal aftereffects with low- and high-frequency free sources].

Short adaptation to sound source approach and withdrawal was carried out within five seconds in free field. Moving adapting and test stimuli were created by means of sequences of low- and high-frequency band noise pulses (0.05-1 kHz and 3-20 kHz) that were changed linearly in amplitude at contrarily directions with two unmoving dynamics. The auditory approach and withdrawal aftereffects were evaluated with the total indexes characterized the shifts of psychometric curves received in different listening conditions for group of eight subjects with normal hearing. Motion aftereffects were observed in case of the spectrum range coincidence for adapting and test stimuli. The effect was at adaptation to approaching and withdrawing high-frequency noise sources, but for low-frequency noise sources one was only at adaptation to approach. The radial motion aftereffects were not revealed in case of discrepancy between spectrum range of adapting and test stimuli. Thereby, the frequency tuning of auditory aftereffect was shown at adaptation to approaching and withdrawing sound stimuii.

[Perception by teenagers and adults of the changed by amplitude sound sequences used in models of movement of the sound source].

The ability to evaluate direction of amplitude changes of sound stimuli was studied in adults and in the 11-12- and 15-16-year old teenagers. The stimuli representing sequences of fragments of the tone of 1 kHz, whose amplitude is changing with time, are used as model of approach and withdrawal of the sound sources. The 11-12-year old teenagers at estimation of direction of amplitude changes were shown to make the significantly higher number of errors as compared with two other examined groups, including those in repeated experiments. The structure of errors - the ratio of the portion of errors at estimation of increasing and decreasing by amplitude stimulus - turned out to be different in teenagers and in adults. The question is discussed about the effect of unspecific activation of the large hemisphere cortex in teenagers on processes if taking solution about the complex sound stimulus, including a possibility estimation of approach and withdrawal of the sound source.

[The auditory aftereffects of radial sound source motion with different velocities].

Auditory aftereffects were evaluated after short adaptation to radial sound source motion with different velocities. Approach and withdrawal of the sound source were imitated by means of rhythmical noise (20 Hz-20 kHz) impulse sequences with arising or diminishing amplitude. They were presented in an anechoic chamber through two loudspeakers placed at 1.1 and 4.5 m from the listener. The adapting stimulus velocities were 0.68, 3.43, 6.92 and 9.97 m/s at adaptation duration of 5 s. By every adaptor speed an aftereffect revealed as distinguishing of psychometric function at approaching and withdrawing adaptors. The direction of function displacements was opposite to one of adaptor motion. Three parameters reflecting alteration of perception after motion adaptation were determined and were compared with control data: an evaluation of stationary test stimuli; a velocity of moving test signal at the point of subjective equality (perceptually unmoving point); a percentage of responses after averaging across all test signals. These parameters of auditory radial motion aftereffect have similar tendencies to change with adaptor velocity. They have demonstrated significant effect at slow motion (0.68 and 3.43 m/s) and small effect at quick motion (6.92 and 9.97 m/s).

[Auditory motion aftereffects with approaching and withdrawing sound sources].

Auditory motion aftereffects with approaching and withdrawing sound sources were investigated in the free field. Radial sound moving image (approaching or withdrawing) was imitated by means of rhythmical noise impulse sequences with arising or diminishing amplitude presented through two loudspeakers placed at 1.1 and 4.5 m from the listener. The adaptation to the auditory approaching and withdrawing exposure caused changing of evaluation by listeners the test signals followed by adapting ones. Stationary test signals were perceived by listeners as moving to the direction opposite to ones presented during adaptation. Stimuli subtly moving to the adapting signals' direction were determined as stationary. The peculiarities of auditory motion aftereffects with approaching and withdrawing sound sources were similar to ones with horizontally moving sound sources.

[Localization of virtual stimuli moving in the median plane by listeners of different age].

Capability for identification of direction of movement of sound images (upward or downward) was studied in listeners of two age groups: 19- 27-year-old (11 subjects) and 55- 73-year-old (9 subjects). Various sound models of movement in the median plane were used as stimuli. Initially, a model of movement was developed based on filtration of broadband noise pulses by sets of non-individualized. i. e., measured in other listeners, head-related transfer functions. These functions corresponded to consecutive positions of the sound sources with the 5.6 degrees step between the space points with coordinates of elevation from -45 degrees to 45 degrees. The signals generated on the basis of transfer function sets of 23 subjects were distinguished by regulatory and value of the spectral minimum shift as well as by dynamic changes of the spectral maximum. Then the dynamic changes typical on non-individual sound images were used to create synthetic models. In these models, movement of sound images in the median plane was simulated either by a regular shift of the spectral minimum in broadband noise pulses or by a combination of the spectral minimum shift with a simultaneous change of the spectral maximum width and power. The obtained data have shown that young listeners with the high capability for vertical localization could identify direction of the sound image movement based on displacement of the spectral minimum in the broadband noise. For identification of direction of the sound image movement, the younger listeners with poor capabilities for vertical localization and the older listeners used dynamic changes of the signal power, which were connected mainly with the spectral maximum range.