Addressing variability in the acoustic startle reflex for accurate gap detection assessment

• Published in: Hearing research Vol. 363; pp. 119 - 135
• Main Authors: Longenecker, Ryan J., Kristaponyte, Inga, Nelson, Gregg L., Young, Jesse W., Galazyuk, Alexander V.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2018
• Subjects: Acoustic startle response magnitude; Acoustic Stimulation; Adaptation, Psychological; Animals; Auditory Pathways - physiopathology; Auditory Perception; Behavior, Animal; Circadian Rhythm; Disease Models, Animal; Female; Gap-induced prepulse inhibition of the acoustic startle reflex; Hearing Tests - methods; Male; Mice, Inbred CBA; Predictive Value of Tests; Prepulse facilitation; Prepulse Inhibition; Reflex, Startle; Reproducibility of Results; Sex Factors; Signal Detection, Psychological; Tinnitus; Tinnitus - diagnosis; Tinnitus - physiopathology; Tinnitus - psychology; ASR; Prepulse facilitation; Acoustic startle response magnitude; PPI; Circadian rhythm; Tinnitus; Gap-induced prepulse inhibition of the acoustic startle reflex; ITI
• ISSN: 0378-5955; 1878-5891; 1878-5891
• DOI: 10.1016/j.heares.2018.03.013

The acoustic startle reflex (ASR) is subject to substantial variability. This inherent variability consequently shapes the conclusions drawn from gap-induced prepulse inhibition of the acoustic startle reflex (GPIAS) assessments. Recent studies have cast doubt as to the efficacy of this methodology as it pertains to tinnitus assessment, partially, due to variability in and between data sets. The goal of this study was to examine the variance associated with several common data collection variables and data analyses with the aim to improve GPIAS reliability. To study this the GPIAS tests were conducted in adult male and female CBA/CaJ mice. Factors such as inter-trial interval, circadian rhythm, sex differences, and sensory adaptation were each evaluated. We then examined various data analysis factors which influence GPIAS assessment. Gap-induced facilitation, data processing options, and assessments of tinnitus were studied. We found that the startle reflex is highly variable in CBA/CaJ mice, but this can be minimized by certain data collection factors. We also found that careful consideration of temporal fluctuations of the ASR and controlling for facilitation can lead to more accurate GPIAS results. This study provides a guide for reducing variance in the GPIAS methodology – thereby improving the diagnostic power of the test. •The ASR is variable, and this variation can contribute to “messy” GPIAS data.•Careful consideration of ITI, sex, circadian, and sensory adaptation factors can reduce ASR variation.•Preceding gaps can inhibit and facilitate the startle response which needs to be appropriately addressed in data analysis.•The benefits and limitations of several GPIAS analyses are considered for tinnitus assessment.