Minimizing the risk of the overstimulation in children after

cochlear implantation

Adam Walkowiak, Artur Lorens, Malgorzata Zgoda, Arkadiusz Wasowski, Henryk Skarżyński, Anita Obrycka, Piotr Henryk Skarżyński

WORLD HEARING CENTER INSTITUTE OF PHYSIOLOGY AND PATHOLOGY OF HEARING

KAJETANY / WARSAW, POLAND

INTRODUCTION  •  The  most  important  stage  in  a  speech  processor  fi8ng  is  the  iden:fica:on  and  se8ng  the  proper  parameters  of  electric  s:mula:on    to  achieve  the  highest  possible  speech  understanding.  

•   This  could  be  done  by  subjec:ve  (psychoacous:c)  or  objec:ve  (electrophysiologic)  measurements    

INTRODUCTION  Objec:ve  measurement  in  CI  fi8ng:  •  EECAP  •  ESRT  •  EABR  •  Cor:cal  responses  

•  Cafarelli  -­‐  Dees  D.,  Dillier  N.,  Lai  W.K.,  von  Wallenberg  E,  van  Dijk  B.  et  al.(2005)  Norma:ve  findings  of  electrically  evoked  compound  ac:on  poten:al  measurements  using  the  neural  response  telemetry  of  the  Nucleus  CI24M  cochlear  implant  system,  AudiolNeurootol.  

•  Walkowiak  A.,  Lorens  A.,  Polak  M.,  Kostek  B.,  Skarżyński  H.,  Szkielkowska  A.,  Skarżyński  P.H.  (2011)  Evoked  stapedius  reflex  and  compound  ac:on  poten:al  thresholds  versus  most  comfortable  loudness  level:  assessment  of  their  rela:on  for  charge-­‐based  fi8ng  strategies  in  implant  users.ORL  J  Otorhinolaryngol.  Relat.  Spec.  

•  Lorens  A.,  Walkowiak  A.  Piotrowska  A.,  Skarżynski  H.,  Anderson  I.  (2004)  ESRT  and  MCL  correla:ons  in  experienced  paediatric  cochlear  implant  users,  Cochlear  Implant  Interna:onal  

   

INTRODUCTION  

During  each  fi8ng  combina:on  of  objec:ve  and  subjec:ve  maesurements  are  u:lized  to  obtain  

op:mal  parameters,  but  it  is  s:ll  a  challenge  in  case  of  children.  

…  s:ll  there  is  a  risk  of  overs:mula:on  

INTRODUCTION  During  fi8ng  of  a  children  our  aim  is  to  develop  percep:on  ability  by  giving  access  to  sounds,  but  

during  this  proces…  

AIM  

The  aim  of  the  study  was  to  determine  if  children  undergoing  rou:ne  fi8ng  could  be  affected  by  overs:mula:on  confirmed  by  

objec:ve  examina:on  as  well  as  parents  ques:onaire.  

MATERIAL  AND  METHOD  •  27 children implanted with Cochlear

(14 patients) and Med-El (13 patients) systems participated in the study

•  Unilateral implantations – no loudness summation

•  Aged from 7 months to 9 years (mean age: 3,7 years)

•  Measurement results collected during standard visit 9 months after first fitting  

MATERIAL  AND  METHOD  •  Stapedius Reflex Threshold (SR Threshold) elicited by

acoustic stimuli –  Data collection – Interacoustics TITAN, decay mode –  Stimulation – WESTRA system, narrow band noise,

frequency: 500Hz, 1000Hz, 2000Hz and 4000Hz, intensity from 40 to 90dB HL

MATERIAL  AND  METHOD  •  Routine subjective assessment of

overstimulation: questionnaire on loudness perception designed in our clinic and distributed among children’s parents –  Questions about different situations like switching the

processor on, changing programs, noisy and school situations etc

–  Parents assessed how often (according their opinion) possible overstimulation happened in situation mentioned above in the scale as below: never – rarely – from time to time – often - always

Percentage of „too loud” responses – mean values for each patient: no „always” nor „often too loud” responses, the rest of response below:

RESULTS  -­‐  Ques:onnaire  

never,  70%  

rarely,  18%  

from  :me  to  :me,  12%  

RESULTS  

ESR  Threshold  

R²  =  0.04779  

0  

10  

20  

30  

40  

50  

60  

70  

80  

90  

100  

0   20   40   60   80   100  

Que

s:on

naire

 results  

Stapedius  Reflex  Threshold  

R²  =  0.04919  

0  

10  

20  

30  

40  

50  

60  

70  

80  

90  

100  

0   20   40   60   80   100  

Que

s:on

naire

 results  

Stapedius  Reflex  Threshold  

SR  Threshold  (mean)  vs  QR  mean        

SR  Threshold  (lowest)  vs  QR  max    QR  results  from    0%  (never  too  loud)  to  100%  

(always  too  loud)          

SR Threshold: red flag when Mean SR Threshold equal or lower than 70dB HL group (SR+) - 3 of 27 children

„normal (safe) value” – Mean SR Threshold grater than 70dB HL group (SR-) - 24 of 27 children

RESULTS  –  SR  Threshold  

[NAZWA  KATEGOR

II]  [WARTOŚ

Ć]  

[NAZWA  KATEGOR

II]    

[WARTOŚĆ]  

Comparison of „TOO LOUD” answers for (SR+) and (SR-) groups

RESULTS  

(SR+)  

(SR-­‐)  

(SR+)  

(SR-­‐)  

(SR+)  

(SR-­‐)  

Never  5%  of  SR+    

Rarely  20%  of  SR+  

From  :me  to  :me  33%  of  SR+  

RESULTS  

1.  Preliminary results show that finding SR Threshold lower or equal to 70dB HL could indicate potential risk of overstimulation during CI use.

2. By adding new objective and subjective tests to the standard test battery it is possible to identify children suspected of overstimulation. Additionally it seems that parents sometimes are too conservative while describing children hearing sensations and obviously it should not be recommended to rely only on their opinions in program loudness assessing.

CONCLUSIONS  

WORLD HEARING CENTER INSTITUTE OF PHYSIOLOGY AND PATHOLOGY OF HEARING

KAJETANY / WARSAW, POLAND