## 3 Results
### Advanced DPOAE Paradigms in Exposed Individuals--Level Sweeps  
As defined in the methods, a detection threshold was identified from level sweep data as the lowest stimulus level that generated a DPOAE (SNR \(\geq\)6 dB and overall level \(>\)\(-\)20 dB SPL) with continued growth as the stimulus level was increased further. A significant change criterion from baseline for detection thresholds was defined as a change of greater than 9 dB. Level sweeps were collected at the two highest frequencies generating a DPOAE from the gross frequency sweep. When each frequency was tested, the level of the higher frequency (L\({}_{2}\)) was fixed while the level of the lower frequency (L\({}_{1}\)) was varied and vice versa. Ideally, this resulted in four input-output functions for each  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & \multicolumn{4}{c}{**Concentrated Frequency Sweep: Mid-Level**} \\ \hline \multirow{2}{*}{**Patient**} & \multirow{2}{*}{ \begin{tabular}{c} **Platinum** \\ Agent** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Number of** \\ **Sessions** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Highest** \\ **Frequency** \\ **DPOAE (kHz)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Session of** \\ **Change** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Frequencies of** \\ **Change (kHz)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Direction of** \\ **Level Change** \\ \end{tabular}  } \\ \hline \multirow{2}{*}{1} & \multirow{2}{*}{Oxaliplatin} & \multirow{2}{*}{2} & \multirow{2}{*}{12} & \multirow{2}{*}{S1 to S2} & \multirow{2}{*}{ \begin{tabular}{c} 7.9-8.0 \\ 10.3-10.4 \\ \end{tabular}  } & \multirow{2}{*}{Increase} \\ \cline{1-1} \cline{6-6}  & & & & & S1 to S2 & 10.7-11.5 & Increase \\ \cline{1-1} \cline{6-6}  & & & & S1 to S3 & 10.7-11.0 & Increase \\ \cline{1-1} \cline{6-6}  & & & & S1 to S3 & 15.3-15.8 & Decrease \\ \cline{1-1} \cline{6-6}  & & & & S1 to S4 & 10.7-12.3 & Increase \\ \cline{1-1} \cline{6-6}  & & & & S1 to S5 & 10.7-11.9 Hz & Increase \\ \hline \multirow{2}{*}{6} & \multirow{2}{*}{Carboplatin} & \multirow{2}{*}{4} & \multirow{2}{*}{8} & \multirow{2}{*}{ \begin{tabular}{c} S1 to S2/S3 \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} 7.9-8.0 Hz \\ \end{tabular}  } \\ \cline{1-1} \cline{6-6}  & & & & S1 to S4 & 7.8-8.0 \\ \hline \multirow{2}{*}{8} & \multirow{2}{*}{Carboplatin} & \multirow{2}{*}{4} & \multirow{2}{*}{10.6} & \multirow{2}{*}{ \begin{tabular}{c} S1 to S2 \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} 7.5-7.6 \& 8.5-8.6 \\ 8.3-9.0, \& 10.3-10.7 \\ \end{tabular}  } \\ \hline \multirow{2}{*}{9} & \multirow{2}{*}{Carboplatin} & \multirow{2}{*}{3} & \multirow{2}{*}{16} & \multirow{2}{*}{\ \begin{tabular}{c} S1 to S3 \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} 10.7-10.3, 12.6-13.1, \\ 14.1-14.3, 14.8-15.0, \\ \& 14.6-16.0 \\ \end{tabular}  } \\ \cline{1-1} \cline{6-6}  & & & & S1 to S3 & 11.5-15.8 \\ \hline \multirow{2}{*}{10 1  1  1 [FOOTNOTE:1]Footnote 1: Indicates no baseline session data, thus S1 indicates the first session. patient. However, due to patient and environment limitations, it was not always possible to run every paradigm in the protocol. Each of the four input-output functions will be described individually. _L2 Fixed, L1 Varied at Highest Frequency with a Present DPOAE._ Four of 10 patients (40%) demonstrated significant changes in their detection thresholds when L1 was varied and L2 was fixed at the highest frequency (f2) with a present DPOAE. Patients 7, 9, and 10 had a significant increase (worsening) or absence for detection threshold identification at subsequent sessions. Patient 7 had four total sessions with an observed detection threshold only for the first session, while patients 9 and 10 had detection thresholds for their first sessions but not for their final (second) session. Patient 6 had no measurable detection threshold for the first three sessions, but session 4 resulted in an identified detection threshold.