###### Abstract  
In this study, we examine the predictive factors influencing the outcomes of voice treatment in patients with voice-related disorders, using the voice handicap index (VHI) as a key assessment tool. By analyzing various personal habits and clinical variables, we identify the primary factors associated with changes when comparing VHI scores before and after voice treatment. For this research, we employed binomial logistic regression, random forest (RF), and a multilayer perceptron (MLP) model to evaluate the effectiveness of voice treatment. The findings reveal that gender (with female patients showing greater improvements in VHI scores compared to male patients), surgical history, voice use status, and voice training status are significant predictors of therapy outcomes. The MLP model demonstrated high accuracy, sensitivity, and specificity, with an area under the curve (AUC) value of 0.87 indicating its potential as a valuable clinical predictive tool; however, the model's relatively low specificity suggests the need for further refinement to enhance its predictive accuracy. The results of this study provide valuable insights for clinicians and speech-language pathologists in developing personalized treatment strategies to optimize the effectiveness of voice therapy. Future research should prioritize the validation of these findings in larger and more diverse population samples. Furthermore, it is essential to explore additional predictive variables in order to enhance the model's accuracy across different types of voice disorders. voice handicap index; predictive factors; voice therapy; voice disorders; machine learning; regression analysis; multilayer perceptron model; clinical effectiveness +
Footnote †: journal: Applied sciences  
daily life does not heavily depend on the use of their voice might not feel particularly inconvenienced. Conversely, if a patient's voice is crucial for their livelihood, hobbies, or professional activities, they may perceive their voice problems as severe and report significant discomfort. Although the degree of self-awareness of voice issues can vary depending on the situation and individual predispositions, it is a very important variable from a therapeutic standpoint and plays a crucial role as an evaluation factor [6; 7]. Accordingly, tools for assessing the self-awareness of speakers with voice problems have been developed and are actively used in clinical practice and research, both domestically and internationally [8; 9; 10; 11]. The most representative of these tools is the voice handicap index (VHI), which is used for voice diagnosis and treatment effect analysis in many countries, including the Republic of Korea. Specifically, the VHI quantifies the degree of handicap a patient feels due to voice disorders before and after treatment, thus serving as a tool to evaluate the effectiveness of treatments. The VHI was designed by [PERSON] et al. in 1997 and remains the most widely used tool to date [12]; it has been adapted into two Korean versions and is widely used in clinical practice at voice clinics in Korea [6; 8]. In recent clinical research settings, efforts have been made to more meticulously analyze the clinical value of evaluating the self-awareness of voice problems, which involves studying the correlation with objective assessments [13; 14; 15; 16]. [PERSON] v. [PERSON] et al. systematically reviewed the literature and conducted a meta-analysis to compare the efficacies of voice therapy, phonosurgery, and a combination of both treatments for vocal fold polyp (VFP) treatment. The study aimed to evaluate the effectiveness of each treatment method by comparing the VHI scores before and after treatment. The results of this study suggest that the VHI can be a valuable tool in guiding treatment decisions for patients with vocal fold polyps [13]. [PERSON] et al. evaluated the characteristics of the VHI after arytenoid adduction (AA) in patients with unilateral vocal fold paralysis (UVFP).