# Long-range temporal correlation in Auditory Brainstem Responses to Spoken Syllable /da/

## TL;DR

This study investigates the long-range temporal correlations in auditory brainstem responses to spoken syllables, revealing multifractal behavior and long-term memory mechanisms in the auditory system at the brainstem level.

## Contribution

It introduces a novel analysis pipeline combining MFDMA with SVD to characterize the scaling behavior and multifractality of sABR signals, demonstrating universality in these properties.

## Key findings

- Normal sABR exhibits long-range correlations with a Hurst exponent around 0.77.
- Multifractality in sABR is primarily due to long-range temporal correlations.
- Long-range correlations reflect slow timescales and information integration in the brainstem.

## Abstract

The speech auditory brainstem response (sABR) is an objective clinical tool to diagnose particular impairments along the auditory brainstem pathways. We explore the scaling behavior of the brainstem in response to synthetic /da/ stimuli using a proposed pipeline including Multifractal Detrended Moving Average Analysis (MFDMA) modified by Singular Value Decomposition. The scaling exponent confirms that all normal sABR are classified into the non-stationary process. The average Hurst exponent is $H=0.77\pm0.12$ at 68\% confidence interval indicating long-range correlation which shows the first universality behavior of sABR. Our findings exhibit that fluctuations in the sABR series are dictated by a mechanism associated with long-term memory of the dynamic of the auditory system in the brainstem level. The $q-$dependency of $h(q)$ demonstrates that underlying data sets have multifractal nature revealing the second universality behavior of the normal sABR samples. Comparing Hurst exponent of original sABR with the results of the corresponding shuffled and surrogate series, we conclude that its multifractality is almost due to the long-range temporal correlations which are devoted to the third universality. Finally, the presence of long-range correlation which is related to the slow timescales in the subcortical level and integration of information in the brainstem network is confirmed.