Visual Evoked Potentials


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Visual Evoked Potentials

  1. 1. Visual Evoked Potentials & Visual Motor Perception in Hearing Loss Esra Ozcebe 1 PhD, Erol Belgin 1 PhD, Meral Topçu 2 MD, Ferhunde Öktem 3 PhD, Bora Eldem 4 MD, Şeniz Özusta 3 MS 1. Hacettepe University Faculty of Medicine, Department of Otorhinolaryngology, Section of Audiology and Speech Pathology, Ankara-Turkey 2. Hacettepe University Faculty of Medicine, Department of Pediatrics Section of Pediatric Neurology Ankara-Turkey 3. Hacettepe University Faculty of Medicine, Department of Child Psychiatry Ankara-Turkey 4. Hacettepe University Faculty of Medicine, Department of Ophthalmology Ankara-Turkey
  2. 2. <ul><li>Visual and auditory abilities are the first two requirements, if one of these abilities is damaged, it requires that healthy one play major role in the individual’s development and learning. </li></ul>
  3. 3. <ul><li>For the children with hearing loss, the major sense is vision as well as the auditory ability left. </li></ul><ul><li>Through the general population, visual impairment are encountered more frequently in hearing impaired individuals, compared to people without hearing loss. </li></ul>
  4. 4. Litareture Vision problems - children with hearing loss 40.4% opthalmological abnor. Hanioglu-Karg ı et al. 2003 44 % visual impairment Armitage, Burke & Buffin, 1995; 57.6% ocular anomalies Elango, Reddy & Shriwas, 1994; 61.1% opthalmological abnor. Siatkowski et al. 1994, 45.3% ocular anomalies Regenbogen & Godel, 1985;
  5. 5. <ul><li>If hearing impaired person have significantly vision problems, this problem can not be explained only with refraction problems . </li></ul><ul><li>What about the rest of visual system? </li></ul><ul><ul><li>Visual attention </li></ul></ul><ul><ul><li>Visual perception </li></ul></ul><ul><ul><li>Visual processing </li></ul></ul><ul><ul><li>CENTRAL VISUAL SYSTEM ????? </li></ul></ul>
  6. 6. <ul><li>Impairment of one sensory system influences the organization and functioning of the remaining senses. </li></ul>
  7. 7. <ul><li>The perceptual deficit theory </li></ul><ul><ul><li>Deficit in one sensory system negatively affects the development of the remaining systems </li></ul></ul><ul><li>The perceptual compensation theory </li></ul><ul><ul><li>Impairment in one sensory system might cause compensatory proficiency in other sensory systems </li></ul></ul><ul><ul><li>(Parasnis, 1983) </li></ul></ul>
  8. 8. Visual perception and visual attention in people with HL <ul><li>Some studies have demonstrated </li></ul><ul><ul><li>Superior </li></ul></ul><ul><ul><ul><li>Parasnis, 1983, Stivalet et al. 1998 </li></ul></ul></ul><ul><ul><li>Equivalent </li></ul></ul><ul><ul><ul><li>Tharpe, Ashmead, & Rothpletz, 2002 </li></ul></ul></ul><ul><ul><li>Poorer </li></ul></ul><ul><ul><ul><li>Quittner, Smith, Osberger, Mitchell, & Katz, 1994; Rothpletz, Ashmead, & Tharpe, 2003, Erden, Otman &Tunay, 2004; Yucel & Derim 2008 </li></ul></ul></ul>
  9. 9. <ul><li>Auditory deprivation from birth leads to compensatory changes within the visual system that enhance attentional processing of the peripheral visual field. </li></ul><ul><li>Proksch & Bavelier (2002) </li></ul>
  10. 10. <ul><li>Visual peripheral field </li></ul><ul><ul><li>Processing of peripheral distractors Deaf </li></ul></ul><ul><li>Visual central field </li></ul><ul><ul><li>Processing of central distractors Deaf </li></ul></ul><ul><ul><li>Proksch & Bavelier (2002) </li></ul></ul><ul><ul><li>Sustained attention Deaf </li></ul></ul><ul><ul><li>Parasnis et al. (2003) </li></ul></ul>
  11. 11. <ul><li>The aim of the study was to investigate visual evoked potentials & visual motor perception in children with severely-profoundly hearing loss </li></ul>
  12. 12. Participants In study group was consisted of 23 prelingual children with severely-profoundly hearing loss and control group was consisted of age and sex matched 23 children with normal hearing. Mean age of children for study group is 9 years 4 months Mean age of children for control group is 9 years 5 months METHODS 114  7.6 123 100 7 16 Conrtol Group 113  7.4 125 97 7 16 Study Group Mean (Std) Max Min Girl Boy Age (month) Gender
  13. 13. The inclusion criteria -1 <ul><li>- minimum 71dB ↑ (PTA) for auditory threshold of both ears in the audiological evaluation of the children for study group </li></ul><ul><li>- Normal hearing acuity was defined by passing a pure tone audiometric screening test a 25 dB HL ISO for 500, 1000, 2000 and 4000 Hz bilaterally for control group </li></ul><ul><ul><li>Audiological examination was done for all participants. </li></ul></ul>
  14. 14. The inclusion criteria -2 <ul><li>N o pathologi c finding in the systemic and neurological examination </li></ul><ul><ul><li>Systemic and neurological examinations of the children have been carried out in the section of pediatric neurology. </li></ul></ul><ul><li>N ormal visual ability of both groups </li></ul><ul><ul><li>The presence of refraction defect has been investigated in the department of ophthalmology. </li></ul></ul>
  15. 15. The inclusion criteria -3 <ul><li>N ormal intelligence quotient (performance IQ) </li></ul><ul><ul><li>Wechsler Intelligence Scale for children –Revised (WISC-R) performance section was used in order to determine performance IQ </li></ul></ul><ul><li>Similar SES </li></ul><ul><li>All hearing impared children </li></ul><ul><ul><li>Attend the same deaf school </li></ul></ul><ul><ul><li>Use TC </li></ul></ul><ul><ul><li>Not amplified before 6 years old (auditory deprivat ion ) </li></ul></ul>
  16. 16. METHOD S <ul><li>Procedures –VEP </li></ul><ul><li>For assessing the central visual function, electrophysiological measurements named visual evoked potentials (VEP) were used. </li></ul><ul><li>VEPs provide a sensitive indication of abnormal conduction in the visual pathway. </li></ul><ul><li>Abnormalities in the amplitude and waveform of the VEPs may also be caused by the loss of axons in the pathway. </li></ul><ul><li>Walsh,Kane& Butler, 2005 </li></ul>
  17. 17. METHOD S <ul><li>Procedures VEP </li></ul><ul><li>VEP ( ST 10 Sensör Medelec ER 94/a VEP ) test applied while patient is in sit down position and the test room was darkened during the test. </li></ul><ul><li>Children were made to sit 80 centimeters far from the monitor with a total view angle of 16 degree, 50 minutes of the view angle of the squares to be evoked and 80% percent of contrast ratio in black and white squares was adjusted. </li></ul>
  18. 18. METHOD S <ul><li>Procedures – VEP </li></ul><ul><li>Stimulus was applied as to make two variations in a second. Wave length potentials of 1-100Hz were recorded by the computer. </li></ul><ul><li>Each of the eyes was tested separately by closing the other one. </li></ul><ul><li>Stimulation was periodically repeated at 128 and its multiples and the average of the responses were taken. </li></ul>
  19. 19. METHOD S <ul><li>Procedures VEP </li></ul><ul><li>According to the 10- 20 international application system, reference electrode was placed on the frontal region and the recorder electrode was placed on the occipital region. The neutral electrode was placed randomly some where on the head. </li></ul>
  20. 20. METHOD S <ul><li>Procedures VEP </li></ul><ul><li>In the assessment of the VEP wave, P100 value marked as P1 that is the first positive wave was taken as a basis and recorded as latency. </li></ul><ul><li>The normal distribution range of P1 value for this age group, (107±10milisecends) is determined by the help of the measurements previously made on a great number of healthy children. </li></ul>
  21. 21. METHOD S <ul><li>Procedure VEP </li></ul><ul><li>The values that have been found above this limit (107±10milisecends) assumed as pathologic. </li></ul><ul><li>Additionally difference of latency between left and right eyes, which exceeds 5 milliseconds, is accepted to be pathologic. </li></ul>
  22. 22. METHOD S <ul><li>Procedures Bender-Gestalt Test </li></ul><ul><li>Bender Gestalt visual motor perception test in order to evaluate visual motor perception. </li></ul><ul><li>Bender Visual Motor Gestalt Test can be defined as a psychological assessment instrument used in the evaluation of visual-motor functioning and visual perception skills in both children and adults. </li></ul><ul><li>Test scores are used in the possible organic brain damage identification and the maturation degree of the nervous system. </li></ul>
  23. 23. METHOD S <ul><li>Procedures Bender-Gestalt Test </li></ul><ul><li>The Bender Gestalt Test is an individually conducted pencil and paper test </li></ul><ul><li>Nine geometric figures are drawn in black. </li></ul><ul><li>Examinee saw these figures one at a time; then, the examinee was asked to copy the figure on a blank sheet of paper. </li></ul><ul><li>Total error scores were compared with normative values. </li></ul>
  24. 24. METHOD S <ul><li>Procedures Bender-Gestalt Test </li></ul><ul><li>These scoring items classified into four groups: </li></ul><ul><ul><li>Distortion </li></ul></ul><ul><ul><li>Rotation </li></ul></ul><ul><ul><li>Perseveration </li></ul></ul><ul><ul><li>Integration </li></ul></ul><ul><li>Items are scored on their presence or absence. The total score is the number of items judged to be a defined error. </li></ul>
  25. 25. RESULTS - VEP Results of the study revealed that VEP findings were found to be pathological in the 26% of the children severely-profoundly hearing loss. (Fisher’s Exact Chi Square Test). p Value Control Group Study Group VEP 0.021 23 17 Normal 0 6 Pathologic
  26. 26. Latency (msn) N1 79.20 78.00 P1 98.40 99.60 N2 132 134 Amplitude (mv) N1-N2 -9.80 -11.40 P1-P2 14.40 15.80 Latency (msn) N1 76.80 76.80 P1 127 127 N2 226 229 Amplitude (mv) N1-N2 -30.60 -34.40 P1-P2 33.00 34.40
  27. 27. Total number of error in Bender-Gestalt Test for study and control group Total numbers of error were analysed with Levene’s t test for independent groups. RESULTS- BENDER-GESTALT 1.022 0.9565 23 Control Group 0.001 2.976 4.6957 23 Study Group p Value S td Mean
  28. 28. Bender-Gestalt Pathologic Bender-Gestalt
  29. 29. RESULTS- BENDER-GESTALT <ul><li>The results of our study revealed that 60.8% of hearing impaired children has abnormal Bender-Gestalt findings (Pearson Chi Square Test ) </li></ul>0.00001 23 9 Normal 0 14 Pathologic p value Control Group Study Group Bender –Gestalt
  30. 30. RESULTS <ul><li>T he cases with abnormal VEP recordings and the cases with pathological Bender-Gestalt finding compared for assessing if there is a relationship between these two tests. </li></ul>
  31. 31. VEP & BENDER-GESTALT RELATION <ul><li>There is no statistically significant relation between two groups (Fisher’s Exact Chi Square Test, p=0.34) </li></ul><ul><li>H owever five of six cases with pathological VEP recordings had also pathological Bender-Gestalt finding (83.3%). </li></ul>5 1 Pathologic 0.34 9 8 Normal VEP Pat hologic Normal p Bender -Gestalt
  32. 32. DISCUSSION <ul><li>V isual evoked potentials and Bender- Gestalt findings were found abnormal in study group. </li></ul><ul><li>Results of the study support the perceptual defiency theory </li></ul>
  33. 33. DISCUSSION VEP Studies There are contradictory results reported in the literature. Adults Deaf poor readers Abnormal VEP Samar et al, 2002 Adults Support the compensation theory Neville, Schmidt, & Kutas, 1983 Adolescents No significant latency differences were found Chlubnová et al. 2005
  34. 34. DISCUSSION Abnormal VEP findings <ul><li>There is evidence from animal and human studies to suggest at least some level of cross-modal reorganization from  one sensory modality when another modality is deprived of input </li></ul><ul><ul><li>Armstrong et al., 2002; Lee et al., 2001 </li></ul></ul>
  35. 35. DISCUSSION Abnormal VEP findings <ul><li>Prominent activity in the temporal cortex in response to visual stimuli, specifically in the auditory cortical regions. </li></ul><ul><ul><li>F inney et al. (2001) </li></ul></ul>
  36. 36. DISCUSSION Abnormal VEP findings <ul><li>VEP study with deaf adults </li></ul><ul><li>d eaf poor readers have abnormal VEP </li></ul><ul><li>Neurobiological evidence that developmental dyslexia exists within the deaf population and is associated with the same underlying magnocellular system deficit. </li></ul><ul><ul><li>Samar, Parasnis & Berent (2002) </li></ul></ul>
  37. 37. DISCUSSION Visual-motor perception studies Our results are consistent with the previously published data Delay in visual motor integration skills Tiber, 1985 Deficiencies perceptual motor areas (visual memory,spatial organization, Gesell copy forms) Mohindra, 1976 Delay in visual motor integration skills Horn et al. 2007 Figure-ground perception, position in space, design copying tests / impaired Erden, Otman & Tunay, 2004 Visual processing deficit Rettenbach et al 1999 Visual motor insufficiency Wiegersma and Van der Velde,1983
  38. 38. Conclusions-1 <ul><ul><li>D etailed investigation techniques should be performed in children with HL </li></ul></ul><ul><ul><li>VEP, may provide further information about underlying pathological conditions such as developmental dyslexia </li></ul></ul><ul><ul><li>Visual-motor perceptions and skills related with other areas should be evaluated in detail </li></ul></ul>
  39. 39. Conclusions-2 <ul><ul><li>Approppriate targets should be set for the educational programs </li></ul></ul><ul><ul><li>Educational programs concerning the other areas where child requires further support, in addition to hearing and speech-language therapy, should be implemented </li></ul></ul>
  40. 40. <ul><li>THANK YOU </li></ul><ul><li>Esra Özcebe PhD </li></ul><ul><li>[email_address] </li></ul>
  41. 41. References <ul><li>Armitage, I.M., Burke, J.P., Buffin, J.T. (1995). Visual impairment in severe and profound sensorineural deafness. Arch Dis Child , 73(1),:53-6. </li></ul><ul><li>Armstrong, B.A., Neville, H.J., Hillyard, S.A., Mitchell, T.V. (2002). Auditory deprivation affects processing of motion, but not color. Brain Res. Cogn. Brain Res . 14, 422–434. </li></ul><ul><li>Bender, I (1938) A visual motor gestalt test and its clinical use. Research Monograph, 3, New York Orthopsychiatric Association. </li></ul><ul><li>Chlubnová, J., Kremlácek, J., Kubová, Z., Kuba, M. (2005) Visual evoked potentials and event related potentials in congenitally deaf subjects. Physiol Res. , 54(6), 577-83. </li></ul><ul><li>Elango,S., Reddy, T.N., Shriwas, S.R. (1994) Ocular abnormalities in children from a Malaysian school for the deaf. Ann Trop Paediatr , 14(2), 149-52 </li></ul><ul><li>Erden, Z., Otman, S., Tunay,V. (2004) Is visual perception of hearing-impaired children different from healthy children? Int J Pediat Otorhinolaryngol ; 68, 281–285. </li></ul><ul><li>Finney, E.M., Fine I., Dobkins KR. (2001) Visual stimuli activate auditory cortex in the deaf. Nat Neurosci , 4, 1171–1173. </li></ul><ul><li>Hanioglu-Kargi ,S., Koksal, M., Tomac, S., Ugurba, S.H., Alpay, A. (2003). Ophthalmologic abnormalities in children from a Turkish school for the deaf. Turk J Pediatr , 45(1), 39-42 </li></ul><ul><li>Horn, D.L. Fagan, M.K, Dillon, C.M, Pisoni,D.B, Richard T. Miyamoto, R.T. (2007) Visual-Motor Integration Skills of Prelingually Deaf Children: Implications for Pediatric Cochlear Implantation Laryngoscope , 117, 2017–2025 </li></ul><ul><li>Koppitz, E. M. (1963) The Bender Gestalt Test for young children . New York: Grune& Stratton. </li></ul><ul><li>Lee, D.S., Lee, J.S., Oh, S.H., Kim, S.K., Kim, J.W., Chung, J.K., Lee, M.C., Kim, C.S. (2001). Cross-modal plasticity and cochlear implants . Nature ,409, 149–150. </li></ul><ul><li>Mohindra, I.(1976) Vision profile of deaf children. Am J Optom Physiol Opt, 53(8):412-9. </li></ul><ul><li>Neville, H. J., Schmidt, A., & Kutas, M. (1983). Altered visual-evoked potentials in congenitally deaf adults. Brain Res , 266, 127-132. </li></ul><ul><li>Ozer S. (2007) Turkish children’s Bender-Gestalt Test performance: A pilot study and Preliminary norms. Perceptual and Motor Skills, 105, 872-882. </li></ul>
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