# Analysis of Facial Cues for Cognitive Decline Detection Using In-the-Wild Data
## 4 Experiments
### Performance Using Head Turns and Movement Features  
Head movement (HM) features are evaluated across various classification tasks, including three-way (ND vs. MCI vs. FMD), four-way (ND vs. MCI vs. FMD vs. HC), and multiple two-way classification problems: MP vs. HC, D vs. Non-D, ND vs. MCI, ND vs. FMD, MCI vs. FMD, ND vs. HC, MCI vs. HC, and FMD vs. HC. Table 8 presents the classification accuracy results for these tasks. The results indicate that HTR and its derivative features (HTR + HTSF) are informative for classification. However, distinguishing FMD from HCs remains the most challenging task. The highest classification accuracy is achieved using HTR + HTSF features, with 59% and 48% accuracy for the three-way and four-way classification tasks, respectively. Additionally, this feature set achieves 92% accuracy in ND vs. FMD classification and 75% in D vs. Non-D classification. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Classification Task** & **Feature** & **Accuracy** & **Precision** & **Recall** & **F-Measure** \\ \hline \multirow{3}{*}{ND/MCI/FMD/HC} & HTR (1) & 45\% & 46\% & 42\% & **59\%** \\  & HTR + HTSF (13) & **48\%** & **50\%** & **46\%** & 53\% \\  & HMSF (54) & 44\% & 45\% & 44\% & 44\% \\ \hline \multirow{3}{*}{ND/MCI/FMD} & HTR (1) & 45\% & 31\% & 46\% & 37\% \\  & HTR + HTSF (13) & **59\%** & **60\%** & **58\%** & **58\%** \\  & HMSF (54) & 53\% & 59\% & 55\% & 53\% \\ \hline \multirow{3}{*}{ND/MCI} & HTR (1) & 53\% & 51\% & 51\% & 46\% \\  & HTR + HTSF (13) & 52\% & 52\% & 50\% & **69\%** \\  & HMSF (54) & **62\%** & **62\%** & **62\%** & 62\% \\ \hline \multirow{3}{*}{ND/FMD} & HTR (1) & 73\% & 76\% & 70\% & 71\% \\  & HTR + HTSF (13) & **92\%** & **89\%** & **89\%** & **89\%** \\  & HMSF (54) & 69\% & 68\% & 66\% & 66\% \\ \hline \multirow{3}{*}{MCI/FMD} & HTR (1) & 71\% & 72\% & 73\% & 72\% \\  & HTR + HTSF (13) & 67\% & 71\% & 69\% & 66\% \\  & HMSF (54) & **90\%** & **92\%** & **88\%** & **88\%** \\ \hline \multirow{3}{*}{MP/HC} & HTR (1) & 72\% & 71\% & 71\% & 71\% \\  & HTR+ HTSF (13) & 64\% & 63\% & 62\% & 62\% \\  & HMSF (54) & **73\%** & **73\%** & **72\%** & **72\%** \\ \hline \multirow{3}{*}{D/Non-D} & HTR (1) & 69\% & 66\% & 64\% & 64\% \\  & HTR + HTSF (13) & **75\%** & **72\%** & **71\%** & **72\%** \\  & HMSF (54) & 73\% & 70\% & 70\% & 70\% \\ \hline \multirow{3}{*}{ND/HC} & HTR (1) & **83\%** & **85\%** & **84\%** & **85\%** \\  & HTR + HTSF (13) & 72\% & 77\% & 73\% & 73\% \\  & HMSF (54) & 74\% & 75\% & 74\% & 74\% \\ \hline \multirow{3}{*}{MCI/HC} & HTR (1) & **74\%** & **74\%** & **74\%** & **74\%** \\  & HTR + HTSF (13) & 69\% & 68\% & 68\% & 68\% \\ \cline{1-1}  & HMSF (54) & 69\% & 68\% & 68\% & 68\% \\ \hline \multirow{3}{*}{FMD/HC} & HTR (1) & **67\%** & **65\%** & **64\%** & **64\%** \\ \cline{1-1}  & HTR + HTSF (13) & 45\% & 25\% & 44\% & 32\% \\ \cline{1-1}  & HMSF (54) & 58\% & 59\% & 58\% & 58\% \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Classification accuracy of four-way, three-way, and two-way classification tasks for the IVA\({}_{\text{S2}}\) dataset, measuring the system performance using individual features with the KNN classifier. The number of features is indicated in parentheses. Moreover, HMSFs prove useful in distinguishing groups with overlapping characteristics, achieving 62% accuracy in ND vs. MCI classification and 90% in MCI vs. FMD classification. In contrast, HTR+HTSF features excel in differentiating groups with more distinct characteristics, such as in three-way, four-way, and two-way (ND vs. FMD and D vs. Non-D) classifications. Certain features perform better in specific two-way tasks. For instance, HTR + HTSF achieves 92% accuracy in ND vs. FMD classification, while the HTR feature alone achieves 72% accuracy in MCI vs. FMD classification. When classifying individuals with memory-related problems against HCs, HTR provides the best performance, with classification accuracies of 83% for ND vs. HC, 74% for MCI vs. HC, and 67% for FMD vs. HC.