Topic of the Lecture: Methods of examination (evaluation) of auditory and vestibular systems

Transcription

1 Topic of the Lecture: Methods of examination (evaluation) of auditory and vestibular systems 1

2 Definition Otolaryngology is the branch of medicine that specializes in morphology, physiology and pathology of ear, nose, upper respiratory system and nearby regions. 2

3 Term - otorhinolaryngology Otos - ear Rhinos - nose Laryngos - larynx/throat Logos -study Greek words abbreviated ORL or LOR 3

4 Peripheral region Sound conduction system 1. Outer ear; 2. Middle ear; 3.Peri- and endolymphal cavities; 4.Basilar membrane; * 5. Tectorial membrane. Sound perception system 1. The organ of Corti (or spiral organ) *- inner ear structures. 4

5 Normal hearing properties: 1. Frequency Range of Human Hearing- from 16 to 20 thsd. Hz. By bone conduction human perceives ultrasound up to 224 thsd. Hz. Normal speech frequency range Hz 2.Unequal sensitivity to various frequencies. 3. Ototopics - capacity of localizing the source of a sound. 5

6 The human auditory system is sensitive to sounds in terms of: - frequency (Hz); - magnitude(db). 130 Db highest intensity sound human is able to perceive. 30 Db low intensity sound. 60 Db lector s speech. Absence of tympanic membrane and ear ossicles hearing loss on Db. Auditory discomfort Db. Rock music: Db in the middle of a hall; Db near stage. 6

7 Auditory system according to Pavlov I.P. is divided as follows: 1. Peripheral region. 2. Transmitting pathway (Central auditory system). 3. Cortical region (primary auditory cortex). 7

8 Anatomical structures of neuronal processing : Spiral ganglion- І neuron Medulla oblongata (nucleus ventralis, nucleus dorsalis) - ІІ neuron; partial decussating Superior olivary complex- ІІІ neuron Inferior colliculi, Medial Geniculate Nucleus- ІV neuron Temporal lobe (superior temporal gyrus) 8

9 Bone conduction 1. Inertial type (low-pitched sounds). 2. Compressional type (high-pitched sounds). 9

10 Hearing Testing І group Speech test. ІІ group- tuning fork tests. Schwabach test. Rinne test. Weber test. Bing test. Federici test. Gelle test. ІІІ group electrophysiological or electroacoustic tests. Subjective methods Objective methods VІ group using conditioned and unconditioned reflexes: Unconditioned auropalpebral and auropupillary reflexes Conditioned - Conditioned Play Audiometry. 10

11 ІІІ group electrophysiological or electroacoustic tests. Subjective methods - Pure tone threshold audiometry; - above-threshold audiometry Si-Si test - small increment sensitivity index test. differential threshold test (Lüscher-Test). - Speech audiometry; - Sesitivity to ultrasound; - Hearing testing in wide frequency range. 11

12 ІІІ group electrophysiological or electroacoustic methods Objective methods - Registration of brainstem and cortical response to sound (computer audiometry/auditory brainstem response (ABR)к а а и и ); - Electrocochleography (ECochG); - Immittance Audiometry; - Evoked Otoacoustic Emissions. 12

13 Audiometry Normal 13

14 Audiometry Conductive hearing loss 14

15 Audiometry Perceptive hearing loss 15

16 Audiometry Combined hearing loss 16

17 Immittance Audiometry Tympanometry Acoustic reflex thresholds Acoustic Reflex Decay Determination of auditory tube passage capability (function) with perforated and non-perforated tympanic membrane 17

18 Immittance Audiometry objective hearing test method Tympanometry 6 tympanogram types (Jerger, 1970) type a (normal) type Аs (otosclerosis) type В (secretory otitis media, perforation of tympanic membrane) type Аd (ossicle chain disfunction) type С (disfunction of auditory tube) type D (adhesive otitis) 18

19 Methods of examination of vestibular system (vestibulometry) 19

20 Functions of vestibular system the semicircular canal system Otolithic organs linear acceleration (on horizontal and vertical plane) gravity Angular acceleration 20

21 Aim of vestibulometry Determination of central and peripheral vestibular syndromes Determination of hypo- or hyperreflexia of labyrinth 21

22 Group of tests 1) 2) Spontaneous vestibular disfunctions Experimental tests (tests with provocative measures ) 22

23 Spontaneous Vestibular Disfunctions 1. Dizziness. 2. Spontaneous past-pointing tests (outstretched hands test, pointing test, Fukuda's vertical writing test number 30, normally deviation no more then 100). 3. Balance system evaluation (Romberg pose; ефа ография (Kephalography?) 60 dots in 60 seconds, Stabilography evaluation of body's center of gravity, walk test). 4.Evaluation of nystagmus reaction: 1) Spontaneous nystagmus; 2) Positional nystagmus; 3) Optokinetic nystagmus; 4) Pressure nystagmus. 23

24 Electronistagmography Registration of potential difference between retina and iris tunic eyeball moving 24

25 Experimental tests Caloric stimulation Rotation tests 25

26 Caloric test 26

27 Caloric test 27

28 Rotation tests 28

29 Posturography 29

30 Vestibulometry in professional selection Otolithic reaction (off vertical axis testing). Multiple repetition of OR (10 tests on right side and as many on the left with 2-3 min. pause) Coriolis Acceleration Tolerance test (test of continuous accumulation of coriolis acceleration in modification of Markarian S.S.) 30

31 Otolithic reaction (off vertical axis testing) 31

32 Vestibulometry in professional selection Otolithic reaction (off vertical axis testing)(voyachek V.G.) somatic reactions 0 reactions are absent 1 slight deviations of the body 2 strong deviations of the body 3 fall out (subject (patient) can not hold himself in the chair) vegetative reactions 0 reactions are absent 1 (subjective feeling of ) nausea 2 paleness or redness of face, changes in heart and breath rate 3 nausea and vomit 32

33 Accumulation test ( 4 support PL swing) 33

34 Vestibulometry in professional (occupational/career) selection Khilov K.L. (provocative factors/irritants) cummulation test 0 degree- after 15 minutes of swinging vegetative reactions are absent; І degree- after 15 minutes of swinging nausea and vomit occurred; ІІ degree- after 5-15 minutes of swinging nausea and vomit occurred; ІІІ degree- in first 5 minutes of swinging nausea and vomit occurred. 34

35 Coriolis Acceleration Tolerance Coriolis Acceleration arises as a result of motion of a particle relative to a rotating system (overlaying of either perpendicular forces) 35