## 4 Discussion  
In this study, we found that the variance, zero-crossing rate, and high energy rate significantly decreased in patients with ADHD after treatment with methylphenidate, an ADHD medication. Thus, the variance, zero-crossing rate, and high energy rate may be useful and objective markers for evaluating the therapeutic effects of ADHD medication in patients with ADHD. Although the total scales did not differ between before and after 1 month of medication, the hyperactivity subscales of SNAP obtained from parents and teachers demonstrated significant decreases after 1 month of medication. The SNAP questionnaire was originally developed to assess ADHD symptoms according to the DSM-III [37,38]. Although several studies have demonstrated that the SNAP score has high validity and reliability [34,39,40], one study reported poor interrater agreement between parents and teachers [5]. In addition, the parents' ratings of inattention and hyperactivity/impulsivity are good predictors for research but not clinical diagnosis. Regarding teacher ratings, only hyperactivity/impulsivity scores are good predictors for both research and clinical diagnosis [40]. The discrepancies between the SNAP scores obtained from the parents and teachers of patients with ADHD can lead to diagnostic uncertainty. In the present study, the hyperactivity subscales of SNAP scores obtained from parents and teachers demonstrated significant decreases after 1 month of medication. For objective evaluation, we used a smart chair equipped with a piezoelectric material to detect the activities of patients with ADHD and noted significant decreases in the variance, zero-crossing rate, and high energy rate values of piezoelectric potentials. The reduction rate of our measurements decreased more than hyperactivity subscales. These results \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Before Treatment** & **After Treatment** & **Reduction Rate** & \(p\) **Value** \\ \hline Variance & 2239.6 \(\pm\) 3314.5 & 480.36 \(\pm\) 871.35 & 78.55\% & 0.0067 * \\ Zero crossing rate & 1.0112 \(\pm\) 0.7547 & 0.4499 \(\pm\) 0.5588 & 55.49\% & 0.0005 * \\ High energy rate & 0.5062 \(\pm\) 0.2815 & 0.2883 \(\pm\) 0.2644 & 43.05\% & 0.0003 * \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison of variance, zero-crossing rate, and high energy rate values before and after treatment. Figure 3: An example of measurements from one patient before and after 1 month of methylphenidate treatment. indicate that our method is an objective and convenient tool for evaluating the therapeutic effects of ADHD medications. Our study is the first to use piezoelectric materials to objectively analyze the therapeutic effects of methylphenidate in patients with ADHD. In addition, the recording instrument was unobtrusive and nondescript, making it easy to use and patients' behavior was not affected by the instrument. The method is a very convenient way to evaluate the therapeutic effects of ADHD medication in consulting rooms. This study had several limitations. First, although the variance, zero-crossing rate, and high energy rate of piezoelectric materials differed significantly before and after 1 month of methylphenidate in patients with ADHD, the sample size was relatively small. The limited number of patients may cause statistically insignificant correlation between the reduction rate of objective measurements (variance, zero cross rate and high energy rate) and subjective measurements from SNAP. Second, we enrolled children with two of the three different ADHD subtypes, and sample sizes for each subtype, especially ADHD-I, were small; thus, the results may not be generalizable to all ADHD subtypes. Future studies should enroll more patients with different ADHD subtypes to investigate the effects of medication on all three subtypes. Third, children's movements in the consulting room could be affected by some uncontrollable factors, such as food intake on the day of assessment, sleep quality before the assessment, and emotions.