2.1.3. Data Synthesis

Data were recorded as mean ± standard deviation. For analysis, weighted values of the stimulation parameters and tremor outcomes were used. Reports of tremor suppression were heterogenous not only in terms of tremor scale, but also follow-up duration. Therefore, tremor outcomes were converted to percentages of tremor reduction and the primary outcome time point was used for each study. Given that the tremor measurements were performed at various follow-up durations, time might have possibly exerted an e ffect on the tremor outcomes owing to disease progression or tremor adaption. For this reason, follow-up durations were split into quartiles and the corresponding tremor outcomes were compared between the four groups.
