title: Summating potential-action potential waveform amplitude and width in the diagnosis of Menière's disease.
abstract: OBJECTIVE
  It has been suggested that analyzing the width and amplitude of the summating potential-action potential (SP-AP) waveforms can increase the sensitivity of electrocochleography. The objective of this study was to evaluate the ratio of SP to AP amplitude (SP/AP) and SP-AP waveform width, as well as the AP latency difference to condensation and rarefaction clicks, for the diagnosis of Menière's disease.
  
  
  METHODS
  This was a prospective, controlled study.
  
  
  METHODS
  We used transtympanic electrocochleography to evaluate 21 patients with definite Menière's disease and 19 normal-hearing patients with other cochleovestibular disorders, comparing SP/AP, AP latency difference, and SP-AP waveform widths as well as calculating the diagnostic sensitivity of these parameters.
  
  
  RESULTS
  Mean SP-AP waveform width was 1.89 ms in the study group and 1.58 ms in the control group. Mean SP/AP was 0.37 in the study group and 0.22 in the control group. The mean product of SP-AP waveform width and SP/AP was 75.26 ms% in the study group and 34.60 ms% in the control group. Mean AP latency difference was 0.13 ms in the study group and 0.07 ms in the control group. For the parameters evaluated, the differences between the groups were statistically significant. In the study group, the sensitivities for the width of the SP-AP waveform, the SP/AP, and the AP latency difference were 33.3%, 52.4%, and 23.8%, respectively.
  
  
  CONCLUSIONS
  The use of the parameters evaluated did not increase the sensitivity of the electrocochleography, whether used in isolation or in conjunction with the SP/AP. Determining SP/AP presented the greatest sensitivity.
authors.affiliation: Department of Surgery, University Hospital, Santa Catarina Federal University, Florianópolis-SC, Brazil. claudioikino@hotmail.com
authors.forename: Cláudio Márcio Yudi
authors.initials: CM
authors.lastname: Ikino
authors.forename: Edigar Rezende
authors.initials: ER
authors.lastname: de Almeida
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001300:Audiometry, Evoked Response / Q000379:methods* / Q000706:statistics & numerical data; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000502:physiology; D015834:Cochlear Diseases / Q000175:diagnosis / Q000503:physiopathology; D018159:Endolymphatic Hydrops / Q000175:diagnosis / Q000503:physiopathology; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008575:Meniere Disease / Q000175:diagnosis* / Q000503:physiopathology; D008875:Middle Aged; D011446:Prospective Studies; D011930:Reaction Time / Q000502:physiology; D012680:Sensitivity and Specificity; D015837:Vestibular Diseases / Q000175:diagnosis / Q000503:physiopathology