MIDDLE EAR MEASUREMENTS IN CHILDREN

MIDDLE EAR MEASUREMENTS IN CHILDREN

1. INTRODUCTION

      Vital in Audiological evaluation

      Tympanometric and Acoustic reflexs

      Provide information about

1. Middle ear
2. Cochlea
3. Auditory nerve
4. Auditory brainstem
5. Focial nerve(cr nerve)

Cross check for other test eg behaviral,ABR

6< months use 1000 HZ (226HZ not accurate)

Otoscupy precedes tympanometric

Quantive description of tympamgram (description and shape)

Infant Acoustic stapedial refers tested using 1000HZ.

Acoustic reflects activator  stimuli for insects ear phones in 2cc cavity mg be reported in Dbhl.

Underestimated in infant ears

(ii) PROCEDURE

                        Biological chach of Tympammeter

                        Multiple frequencies probe tone generator

                        Rapid pressure sweet rate best for children (time span)

                       Seal should be hermetic

                      Straighten pinna gently

                     Most equipment have start pressure at +200dBa

                    Sweep pressure fm positive to negative

                    Negative to positive sweeps- increased completely

(iii) INTERPRETATION

 1.  Types A-normal

              B-Flat( Effusion perforation)

             C-Excessive Negative pressure

         As-Normal pressure peal

                 Abnormal shallow amphtude (Otosclerosis)

.Normal Limits

      Flat tympamgram,large canal volume (Vea>?cm3) =potent Eust tube or perforation

     Flat –Normal Ear canal Volume, or Low peal= One low peal

     Wide Typammetric width (  <0.2 mm nos) in 6-30 months.

    Peals y>0.3 mm hos, TW >235Db pa(Roushet al,1995) MEE

2. Acoustic Stapedial Reflects Tests

Follow tympammetry

Activator admittance  for 226 HZ probe tone 0.02 or 0.03 mm hos

In infants 226HZ-results in absent reflects in majority with 1000 Hz ready all report measurably remarks reflects.

ASR thresholds for children= adult values

(iv) NORMATIVE VALUES

1. TYMP         STATIC ADMITTANCE    Tympametric width  Canal Volume

Children  3-1o yr old          Y                              TW/GR                         Vea

                                             0.52                         80-15g                      0.3-0.9

                                                                                *60-150                   0.4-1

                    Fail <0.2 dapa

                             <0.3,+                                >160                           >1.0

                               (0-2-0.9)

ADULTS 18yrs       0.30-1.70                      51-114                   0.9-2.0

                               0.3dapa                            >115                      >2.0

                               <0.4+

                               0.3-1.4m                            50-110               0.6 to 1.5

2.ACOUSTIC REFLEXES

                            80-85 Dbhl IN 500 TO 4000 HZ

                             BBN is 10dB lower than tonal stimuli(Wilson Margolis, 1990)