Auditory evoked potentials: predicting speech therapy outcomes in children with phonological disorders

Abstract

OBJECTIVES:This study investigated whether neurophysiologic responses (auditory evoked potentials) differ between typically developed children and children with phonological disorders and whether these responses are modified in children with phonological disorders after speech therapy.METHODS:The participants included 24 typically developing children (Control Group, mean age: eight years and ten months) and 23 children clinically diagnosed with phonological disorders (Study Group, mean age: eight years and eleven months). Additionally, 12 study group children were enrolled in speech therapy (Study Group 1), and 11 were not enrolled in speech therapy (Study Group 2). The subjects were submitted to the following procedures: conventional audiological, auditory brainstem response, auditory middle-latency response, and P300 assessments. All participants presented with normal hearing thresholds. The study group 1 subjects were reassessed after 12 speech therapy sessions, and the study group 2 subjects were reassessed 3 months after the initial assessment. Electrophysiological results were compared between the groups.RESULTS:Latency differences were observed between the groups (the control and study groups) regarding the auditory brainstem response and the P300 tests. Additionally, the P300 responses improved in the study group 1 children after speech therapy.CONCLUSION:The findings suggest that children with phonological disorders have impaired auditory brainstem and cortical region pathways that may benefit from speech therapy.

Potencial Evocado Auditivo de Média Latência (PEAML) em crianças e adolescentes brasileiros: revisão sistemática

“…Considering the results described for individuals with typical development or normal hearing controls, the average Pa latency (15,17,18) ranged from 28.91 to 35.85 ms, an average of 32 milliseconds of the reported values. On the other side, the Na-Pa amplitude (13,15,(17)(18)(19) ranged from 0.83 to 2.74 uV with 1.57 microvolts in average between the reported values. These values are consistent with other national studies (7,21) and international normality parameters (1,4,5,22) .…”

“…As a result of the initial search, 1315 articles were identified, of which eight (12)(13)(14)(15)(16)(17)(18)(19) met the inclusion criteria and were considered relevant for the sample of this study. The search process and selection of the articles present in this review are outlined in the Figure 1.…”

“…The literature search showed few studies with higher level of evidence (7,20,21) , which did not allow generalizations regarding the findings and hampered the standardization of testing protocols and the possibility to establish normative data of the MLR in different populations. Two studies (15,19) were conducted with almost experimental methodology and agreed with the authors (22,23) that indicate the comparison of pre and post-therapeutic intervention middle latency responses as an effective strategy to monitor changes in the auditory pathway. The MLR is a potential greatly influenced by endogenous artifacts (postauricular reflex, relaxation state, etc.)…”

“…The same tests were used in other studies (7,(22)(23)(24) and were effective in the identification of differences in the pre and post-intervention MLR response and in the comparison of the ear and electrode effects. Although the criteria for acquisition and interpretation of the MLR are variable, researches involving the use of this potential show its importance for the evaluation of the central auditory pathway in an objective way and to aid in the neurological diagnosis of injuries and central dysfunctions (12)(13)(14)(15)17,19,32) .…”

“…Even in normal hearing individuals without associated comorbidities, the MLR changes were reported in 17.4% (12) to 64% (14) of the children and adolescents present in the evaluated studies. In both studies with lower (12) (14) Na and Pa peak latency; Na-Pa peak-to-peak amplitude to calculate EA or EE with 50% cutting point NI NI ANOVA, CI Schochat et al, 2010 (15) Latency at the most negative peak between 14-21ms (Na) and positive between 21-45ms (Pa); Na-Pa peak- (19) Na and Pa peak latency; Na-Pa and greater (14) prevalence of alteration of the potential in individuals without complaints or hearing functional alterations, the first considered only the latency and amplitude of the Pa wave and the second, the Na and Pa latency and the amplitude of the Na-Pa interpeak. Studies show the Na-Pa amplitude as the most sensitive parameter to MLR changes, through the analysis of the ear and electrode effect (20)(21)(22) .…”