## 3 Results  
In line with the first aim of the study, we were able to record c and oVEMP responses from both the left and right ears with mono-aural ACS and tendon hammer Fz tap BCV during simultaneous monopolar DBS in five participants with PD. As per aim two, post-filtering of the DBS signal noise revealed the presence of c and oVEMP responses in the five participants. See Figure 1 for a typical example of cVEMP non-filtered (top row) and filtered (bottom row) traces and Figure 2 for oVEMP non-filtered (top row) and filtered (bottom row) traces. c and oVEMP peak-to-peak amplitudes and latencies of the first two early VEMP reflex peaks are given in Tables 1 and 2, respectively. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**\textbackslash{}TEMP ACS Left Ear**} & \multicolumn{4}{c}{**\textbackslash{}TEMP ACS Right Ear**} & \multicolumn{4}{c}{**\textbackslash{}TEMP BCV Left Ear**} & \multicolumn{4}{c}{**\textbackslash{}TEMP BCV Right Ear**} \\ \hline \multirow{3}{*}{**Subject**} & **Pp Amp** & **p1** & **n1** & **p1** & **p1** & **n1** & **p1** & **n1** & **p1** & **n1** & **p1** & **n1** & **n1** & **n1** & **n1** & **n1** & **n1** & **n1** & **n1** & **n1** & **n1** \\  & **\(\mu\)V** & **Latency** & **Latency** & **p1** & **uV** & **Latency** & **Latency** & **p1** & **uV** & **Latency** & **Latency** & **p1** & **uV** & **Latency** & **Latency** & **Latency** \\ \hline P1 & 88.07 & 12.75 & 20.75 & 89.35 & 13.0 & 20.25 & 30.12 & 13.5 & 18.50 & 105.20 & 14.5 & 23.0 & \\ P2 & 39.82 & 13.0 & 20.0 & 41.0 & 12.0 & 20.00 & 70.92 & 15.0 & 22.25 & 75.92 & 14.75 & 22.0 & \\ P3 & 0 & - & - & 0 & - & 29.41 & 16.25 & 25.25 & 0 & - & - & - \\ P4 & 0 & - & - & 0 & - & - & 30.83 & 13.75 & 20.25 & 71.13 & 13.75 & 20.75 & \\ P5 & 0 & - & - & 177.31 & 13 & 19.25 & 176.67 & 13 & 19.25 & 143.00 & 13 & 19.5 & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Left and right ears’ cervical vestibular evoked myogenic potential (cVEMP) peak-to-peak amplitudes in μV and n10 and p15 peak latencies in ms for each five participants in response to ACS and BCV stimations. ACS—air-conducted stimulus; BCV—bone-conducted vibration. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**\textbackslash{}TEMP ACS Left Ear**} & \multicolumn{4}{c}{**\textbackslash{}TEMP ACS Right Ear**} & \multicolumn{4}{c}{**\textbackslash{}TEMP BCV Left Ear**} & \multicolumn{4}{c}{**\textbackslash{}TEMP BCV Right Ear**} \\ \hline \multirow{3}{*}{**Patient**} & **Pp Amp** & **n1** & **P1** & **Pp Amp** & **n1** & **p1** & **p1** & **p1** & **Pp Amp** & **n1** & **p1** \\  & **\(\mu\)V** & **Latency** & **Latency** & **uV** & **Latency** & **Latency** & **uV** & **Latency** & **Latency** & **uV** & **Latency** & **Latency** & **Latency** \\ \hline P1 & 0 & - & - & - & 0 & - & - & 2.01 & 9.25 & 14.50 & 2.0 & 8.5 & 14.0 \\ P2 & 0 & - & - & 3.80 & 10.5 & 15.5 & 15.39 & 9.5 & 15.75 & 15.23 & 9.0 & 15.25 \\ P3 & 0 & - & - & 0 & - & - & 0 & - & - & 4.61 & 10 & 16.5 \\ P4 & 0 & - & - & 0 & - & - & 0 & - & - & 0 & - & - \\ P5 & 0 & - & - & 2.12 & 7 & 13.5 & 13.21 & 8.25 & 14.5 & 10.62 & 8.25 & 13.75 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Left and right ears’ ocular vestibular evoked myogenic potential (oVEMP) peak-to-peak amplitudes in μV and n10 and p15 peak latencies in ms for each five participants in response to ACS and BCV stimations. ACS—air-conducted stimulus; BCV—bone-conducted vibration. Figure 1: Graphs showing left and right ears’ cVEMP responses to ACS and BCV recorded from one participant (P2) with DBS ON. Raw data (unfiltered) are shown on the top row and filtered data are shown on the bottom row. Note the scale difference between the unfiltered and filtered graphs. Vertical axis: amplitude in μV; horizontal axis: latency in ms. ACS—air-conducted stimulus, BCV—Bone-conducted vibration, DBS—deep brain stimulation, cVEMP—cervical vestibular evoked myogenic potential. Aim three of the study was to validate the post-filtering analysis of the VEMP response.