Auditory evoked potential (P300) in cochlear implant users: a scoping review

Introduction P300 auditory evoked potential is evoked by a long latency auditory stimulus, which provides information on neural mechanisms underlying central auditory processing, considered an objective and non-invasive technique to study the auditory central nervous system. Objective To identify and gather scientific evidence regarding the P3 component in adult cochlear implant users. Methods Scoping review of scientific literature, in the search of original articles in Portuguese, Spanish and English, published between 1991 and May 2018, in the following database websites: PubMed / Medline, Embase, LILACS and Web of Science. Results A total of 87 articles were identified and exported to the search software Rayyan for study selection - 58 were from Embase, 26 from PubMed and 3 from Web of Science. There were no articles found on LILACS. From those 87 articles, 16 were excluded for being duplicated. Then 71 articles were selected for title, authors, yeas and abstract scanning, from which 50 articles were excluded. From the 21 final articles for full reading, one was excluded for not performing P300, leaving us with 20 selected articles. Conclusion This review has contributed with evidence that indicates how important it is to include speech stimulation when measuring P300. Regardless of the stimulus being used for P300 elicitation, a pattern of results can be seen a higher latency and a lower amplitude in CI users.


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Considering P300's clinical applicability as a possible tool for neuronal plasticity 125 monitoring during CI hearing rehabilitation, our study raised the following question:

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"What is the scientific evidence in regards to P3 measurements in CI users?", according to

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It is worth noting that this study's relevancy is that it offers perspectives that 133 could help us understand the relationships between these measurements and the 134 possibilities of monitoring, decision-making and planning the intervention process, as well 135 as patient and family orientation. OR "Event-Related Potential, P300" OR" P300 Event-Related Potential" OR "P300 Component" OR "P300 Components" OR "Event-Related Potentials, P3" OR "Event Related Potentials, P3" OR "P3 Event-Related Potentials" OR "Event-Related Potential, P3" OR "P3 Event Related Potentials" OR "P3 Event-Related Potential" OR "Evoked Potentials, P300 Component" OR "P300 Event-Related Potentials" OR "P300 Event Related Potentials" OR "P3b Event-Related Potentials" OR "Event-Related Potential, P3b" OR "Event-Related Potentials, P3b" OR "P3b Event Related Potentials" OR "P3b Event-Related Potential" OR "P3a Event-Related Potentials" OR "Event-Related Potential, P3a" OR "Event-Related Potentials, P3a" OR "P3a Event Related Potentials" OR "P3a Event-Related Potential"

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For data extraction, a standardized script was used, with characterization of each 208 study (author, year, methodological aspects and main results), and data related to the type 209 of stimulus used and specified according to P300 measurements.

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For results presentation, descriptive data analysis was conducted, including tables 211 with the studies' synthesis, searching for answers regarding latency and amplitude 212 measurements found in each article, as well as the variables and parameters identified 213 between them. We used the Preferred Reporting Items for Systematic Reviews and Meta- Neural correlates of auditory-cognitive processing in older adult cochlear implant recipients." To compare P300 in elderly CI users and normal-hearing older adults. To compare music irregularities and physical oddballs between CI users and normal-hearing individuals.

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As for the origin of these studies, they were all published in English, 19 of them 231 were published in international journals and only one was published in a Brazilian national 232 journal, revealing the lack of national articles about this subject.

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In regards to the parameters used to elicit P300, such as the details on which 234 stimulus was used, these data are further described in chart 4. E16 9 CI users e 10 normal-hearing P3 prolonged and decreased in CI users with age above 60.

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13 CI users e 13 normal-hearing P300 prolonged in CI users exposed to noise.

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5 extra cochlear CI and 9 intra Latency levels were prolonged in extra and intra cochlear CI users, in cochlear comparison to normal-hearing individuals. Results with pure tone were similar and there was correlation between amplitude and speech perception.
E19 9 CI users e 10 normal-hearing A relationship was found between P300 amplitude for 500 and 1000Hz and /a/,/i/ and speech perception tests. 263 used speech and pure tone, and only one used music stimulation (Table 3). We can 264 understand why the option of studying cortical auditory potentials with a speech stimulus 265 is so important, once the goal in this kind of intervention is to give the patient access to 266 speech sounds. Another important factor to consider is the advantage in associating 267 objective tests, such as electrophysiological tests, to behavioral assessment (like speech 268 perception tests), as a novel resource to understand the auditory system and also the 269 limitations of neuronal plasticity and its consequences in speech perception performance.
270 This perception of the need to adjust a pattern in parameters -in this case, the stimuli -for 271 auditory evoked potentials has had an increased importance over the last decade, which 272 can be seen in this study, with publications from 2005 on (

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As we analyze the influence of the kind of stimulus used to elicit P300, the absolute 309 latency of P3 was considered prolonged in the cortical potential exam on six out of 11 310 studies that used pure tone (E2 18 E3 19, E4 20, E5 E10, E17). When pure tone and speech 311 were both used, study E18 [35] found prolonged latency of the P3 component also.

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Age was an aspect highlighted by study E16 as a possible reason for a rise in

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Absolute latency may be associated with time of CI experience and some of the 315 studies that used pure tone showed that, with more time of experience, the absolute 316 latency showed reduced levels (E1 E7 and E9).

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Amplitude was also a parameter of interest in this integrative review. There were no 318 differences between the amplitude of P3 for monaural and binaural conditions (E5).
319 However, it was one of the parameters which showed correlation between pure tone and 320 speech stimuli and the speech perception test results (E18 and E19).

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Hearing loss etiology should also be considered when higher P3 component 322 latencies are found and when there are poor speech perception results, as identified in 323 E12 28 , with meningitis patients and, therefore, authors suggest neuropsychological 324 evaluation in the test battery for CI indication, as a measurement to prevent poor prognosis 325 in CI results.

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The effect of music stimulation stood out among other stimuli used to elicit P300,

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Regardless of which stimulus was used to elicit P300, we can notice a pattern in 337 latency increase and amplitude decrease in CI users.

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Experienced time of CI use and the speech tests' results seem to be related to the 339 latency and amplitude measurement results of the P3 component.