## 2 Materials and Methods
### CDSS Implementation  
The decision support system for assessing the nutrition-related geriatric syndromes was implemented using the previously discussed XAI-based risk assessment model and system concept. This CDSS was deployed at the clinical department of geriatrics of Lithuanian University of Health Sciences (accessible online: [[https://gerimodis.lt](https://gerimodis.lt)]([https://gerimodis.lt](https://gerimodis.lt)), accessed on 9 December 2021), where it is used by physicians with different levels of experience in geriatrics. The proposed system uses screening questions for four geriatric syndromes (Figure 5) and medically approved questionnaires (Figure 6). Numerical and/or verbal symptoms estimates and total estimates of the answers to the questions in each questionnaire serve as input data for the CDSS. The diagnosis process begins with answering screening questions regarding four nutrition-related geriatric syndromes. Each syndrome is defined by four characteristic questions (Figure 5). The CDSS takes into account the mutual influence of the syndromes and gives the initial prognostic answer, and then the specialist continues by filling out questionnaires related to syndromes (Figure 6). The questionnaires were selected according to international geriatric practice, adapted and complemented based on the expertise of the specialists of the clinical department of geriatrics of Lithuanian University of Health Sciences. The MNA-SF scale [25] was used for malnutrition (Figure 6a), the EAT-10 dysphagia screening tool [29] was used for orophangel dysphagia (Figure 6b), the Edinburgh Feeding Evaluation in Dementia Scale [2] was used for dementia (Figure 6c), the set of questions formed using the ESPEN guidelines on clinical nutrition and hydration in geriatrics [1] was used for dehydration (Figure 6d). These questionnaires are given in Appendix A. Since the CDSS is based on fuzzy logic, the scores provided by the questionnaires are converted into verbal estimates: \"good\", \"might be bad\", \"bad\" (\"Model estimate\" tables in Figure 6). For the MNA-SF scale, good nutritional status corresponds to 0-2 points, suspicion of malnutrition corresponds to 3-6 points, and malnutrition corresponds to 7-14 points. Please note that the MNA-SF scale used in the CDSS is modified compared to the original one, presented in the work of [25]. The modified scale has an inverted \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{4}{c}{**General Threat of Syndromes (Threat, Certainty)**} \\ \cline{2-5}  & **Malnutrition (M)** & **Oropharyngeal** & **Eating Disorders** & **Dehydration** \\  & **(M)** & **Dysphagia (OD)** & **in Dementia (D)** & **(DH)** \\ \hline Pessimistic & LARGE & MEDIUM & SMALL & LARGE \\ diagnosis & 0.228 & 0.396 & 0.560 & 0.475 \\ \hline Optimistic & MEDIUM & SMALL & NOT & MEDIUM \\ diagnosis & 0.772 & 0.604 & 0.440 & 0.525 \\ \hline Most likely & MEDIUM & SMALL & SMALL & MEDIUM \\ diagnosis & 0.772 & 0.604 & 0.560 & 0.525 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: An example of diagnostic advice produced by the model of XAI-based CDSS for one patient. scoring system, where malnutrition is indicated by a higher score. For the EAT-10 dysphagia screening tool, the absence of the disorder corresponds to 0-2 points, the suspected dysphagia is indicated by 3-10 points, and the dysphagia corresponds to 11-40 points. For the Edinburgh feeding evaluation in the dementia scale, the absence of eating disorder in dementia corresponds to 0-5 points, the suspected eating disorder in dementia is indicated by 6-10 points, and eating disorder in dementia corresponds to 11-20 points. For dehydration, an original set of questions was formed using the ESPEN guidelines on clinical nutrition and hydration in geriatrics. The absence of dehydration corresponds to 0-5 points, the possible dehydration is indicated by 6-10 points, and the dehydration corresponds to 11-40 points. Figure 5: Screenshot of the CDSS initial symptoms estimation questionnaire.