Verificação das respostas do mismatch negativity (MMN) em sujeitos adultos normais

Abstract

Mi smatch Negativity (MMN) is used to evaluate the central auditory system. Aim: to characterize the MMN, in normal subjects. Materials and methods: prospective study, 12 subjects, six males and six females, between the ages of 18 and 24. "Mann-Whytnei" test. Exams: Pure Tone Audiometry (PTA), Tympanometry, Otoacoustic Emissions and Short and Long Latency Auditory Potentials (MMN). Results: in MMN variable amplitude, the mean value was of -2.757 µV and -3.548 µV, CZA1 and CZA2; of 1.435 µV and -1.867 µV, CZA1 and CZA2. In variable and medium latency, we found in 150.7ms and 153.2ms, CZA1 and CZA2; in 170.4ms and 184.0ms, CZA1 and CZA2 -for females and males respectively. Conclusion: related to latency, there was significant statistical difference between the genders in relation to CZA1 and CZA2; and it was lower for females and higher for males.

Aplicabilidade do Mismatch Negativity na população infantil: revisão sistemática de literatura

“…The scientific literature emphasized the importance of verifying the use of MMN in the infant population and the need to know its applications in clinical practice (12) . Authors reported that MMN can be used to objectively evaluate patients with difficulty or impairment in communication, auditory discrimination, difficulty to respond consistently to stimulation, and in noncollaborative individuals, in order to evaluate the discrimination of different acoustic stimuli (1,41) . This review confirms that described in the literature, when it certifies that MMN applications are broad and include children with reading and writing difficulties, AD, dyslexia, stuttering, autism spectrum disorder, ADHD, auditory processing disorder, repetitive otitis …”

“…Changes in any portion of the auditory pathway prevent the development of these abilities from occurring fully (1) . Therefore, it is recommended that, in order to obtain an audiological diagnosis with more accuracy, objective and subjective assessment methods should be associated (2) .…”

“…Therefore, it is recommended that, in order to obtain an audiological diagnosis with more accuracy, objective and subjective assessment methods should be associated (2) . It is also important that tests capable of investigating auditory processing be incorporated into clinical practice (1) and, according to the American Speech-Language-Hearing Association (ASHA), it is recommended to use the electrophysiological evaluation for the Study of auditory abilities (3) . Mismatch Negativity (MMN) is a long-latency auditory evoked potential that objectively portrays an electrical brain response in processing skills, sound discrimination, auditory memory (4,5,6) , and involuntary attention (7) .…”

“…This potential has as main generator the auditory cortex and receives contributions from the frontal cortex, thalamus and hippocampus (8) . It is a cerebral automatic response, promoted by any discriminable change in some repetitive aspect of auditory stimulation (6,9,10,11) , indicating a mismatch between the new sensory input, in relation to a stored standard stimulus In the short-term auditory sensorial memory (1,6,12) . MMN is obtained by subtracting the response evoked by the rare stimulus in relation to the standard stimulus presented (4,9,10) , and the result appears as a wave with negativity (6,9) .…”

“…MMN is a procedure that has a good correlation with the results found in subjective evaluations that, similarly, analyzed the ability of auditory discrimination (6,13) . Its main advantage, compared to other exams, is that the wave appears independently of the attention of the individual to the presented sound stimuli (1,4,6,7,10,14) , that is, it can be registered without the influence of the attention of the subject and without requiring tasks, making it particularly suitable for clinical studies in evaluating the child population (4,11) . Studies have shown that MMN can be a very useful evaluative means for recognizing changes in language (4,9) in children due to the possibility of assessing auditory processing deficit at an early age (9,13,15) Capable of analyzing neurophysiological plasticity (13) .…”