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Department of Speech and Hearing, School of Allied Health Sciences, Manipal University, Manipal, India
Publication date: 2015-03-31
Corresponding author
Aju Abraham   

Aju Abraham, Department of Speech and Hearing, School of Allied Health Sciences, Manipal University, Manipal, India, e-mail:
J Hear Sci 2015;5(1):41-46
It has been reported that in prelingually deafened adults there is maturation of the late latency response (LLR) after rehabilitation using cochlear implants. Other evidence suggests that the auditory system, like any other sensory system, receives multimodal stimulation, a factor which could help the auditory system mature even in the absence of any auditory input. The current study was done on two prelingually deaf adults who had not received rehabilitation, and their latencies were within the normal mature range, suggesting their auditory cortex responses were maturely developed prior to rehabilitation.

Material and Methods:
Two male participants took part in the study: one was 21 years old and the other was 36, and both had congenital profound hearing loss. Using pure tone thresholds obtained earlier, a strong class hearing aid (Siemens Infiniti Pro SP) was programmed using NOAH software and fitted to the right ear using the NALNL-1 fitting formula. As an objective measure of verification of hearing aid effect, auditory P1, N1, P2, and N2 were recorded using the free-field facility available in the IHS SmartEP system: a 1000 Hz pure tone was presented at 70 dB SPL (30 dB SL) and 50 dB SPL (10 dB SL) from a loudspeaker at a distance of 1 m and 45° angle.

The latencies of P1, N1, P2, and N2 for both participants were recorded for 70 and 90 dB HL; all latencies were well within normal limits.

The results indicate that, with adequate amplification, a mature response from the auditory cortex can be obtained even in adults who have profound hearing loss and who have been deprived of auditory stimuli since a prelingual age

Weitzman ED, Graziani LJ. Maturation and topography of the auditory evoked response of the prematurely born infant. Electroencephalogr Clin Neurophysiol, 1967; 23(1): 82–3.
Knudsen, EI. Sensitive periods in the development of the brain and behavior. J Cogn Neurosci, 2004; 16(8): 1412–25.
Skuse H. Extreme deprivation in early childhood. In: Bishop D, Mogford K (eds.), Language Development in Exceptional Circumstances. Erlbaum, Hillsdale, 1993;. 29–46.
Ruben RJ. A time frame of critical/sensitive periods of language development. Indian J Otolaryngol Head Neck Surg, 1999; 51(3): 85–9.
Kral A, Hartmann R, Tillein J, Heid S, Klinke R. Delayed maturation and sensitive periods in the auditory cortex. Audiol Neurootol, 2001; 6(6): 346–62.
Syka J. Plastic changes in the central auditory system after hearing loss, restoration of function, and during learning. Physiol Rev, 2002; 82(3): 601–36.
Hartmann R, Kral A. Central responses to electrical stimulation. In: Zeng FG, Popper AN, Fay RR (eds.), Cochlear Implants: Auditory Prostheses and Electric Hearing. Springer, New York, 2004; 213–85.
Kral A, Hartmann R, Tillein J, Heid S, Klinke R. Congenital auditory deprivation reduces synaptic activity within the auditory cortex in a layer-specific manner. Cereb Cortex, 2000; 10(7): 714–26.
Hubka P, Kral A, Klinke R. Input desynchro-nization and impaired columnar activation in deprived auditory cortex revealed by independent component analysis.In: Syka J, Merzenich MM (eds.), Plasticity and Signal Representation in the Auditory System. Springer Verlag, Berlin, 2004; 161–5.
Kral A, Tillein J, Heid S, Hartmann R, Klinke R. Postnatal cortical development in congenital auditory deprivation. Cereb Cortex, 2005; 15(5): 552–62.
Larkum ME, Zhu JJ, Sakmann B. A new cellular mechanism for coupling inputs arriving at different cortical layers. Nature, 1999; 398(6725): 338–41.
ANSI. Maximum permissible ambient noise levels audiometric test room. ANSI-S3.1-1999 (R2003). New York. American National Standards Institution.
Barnet AB. Auditory evoked potentials during sleep in normal children from ten days to three years of age. Electroencephalogr Clin Neurophysiol, 1975; 39(1): 29–41.
Čeponienė, Kushnerenko E, Fellman V, Renlund M, Suominen K, Näätänen R. Event-related potential features indexing centralauditory discrimination by newborns. Brain Res Cogn Brain Res, 2002; 13(1): 101–13.
Molfese DL. Evoked Potential Analysis and Collection System 1988. (EPACS) USA.
Molfese D, Molfese V. The continuum of language development during infancy and childhood: Electrophysiological correlates. In: Rovee-Collier C, Lipsitt L, Reese R (eds.), Progress in Infancy Research. vol. 1. Mahwah, NJ: Erlbaum; 2000; 251–87.
Sharma A, Gilley PM, Dorman MF, Baldwin R. Deprivationinduced cortical reorganization in children with cochlear implants. Int J Audiol, 2007; 46(9): 494–9.
Ramachandran VS, William H. The perception of phantom limbs. The D. O. Hebb lecture. Brain, 1998; 121: 1603–30.
Finney EM, Fine I, Dobkins KR. Visual stimuli activate auditory cortex in the deaf. Nat Neurosci, 2001; 4(12): 1171–3.
Finney EM, Clementz BA, Hickok G, Dobkins KR. Visual stimuli activate auditory cortex in deaf subjects: evidence from MEG. Neuroreport, 2003; 14(11): 1425–7.
Yoshinaga-Itano C1, Sedey AL, Coulter DK, Mehl AL. Language of early- and later-identified children with hearing loss. Pediatrics, 1998; 102(5): 1161–71.
Pockett S, Purdy SC, Brennan BJ, Holmes MD. Auditory click stimuli evoke event-related potentials in the visual cortex. Neuroreport, 2013; 24(15): 837–40.
Burdo S, Razza S, Di Berardino F, Tognola G. Auditory cortical responses in patients with cochlear implants. Acta Otorhinolaryngol Ital, 2006; 26(2): 69–77.
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