## 3 CAD Systems of Brain Disorders Based on Multimodal Fusion
### Multimodal Fusion Techniques Proposed in Literature: Description, Advantages and Disadvantages
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Reference**} & \multirow{2}{*}{**Multimodal Classifier**} & \multirow{2}{*}{**ADNI Subjects**} & \multirow{2}{*}{**Modalities**} & \multicolumn{6}{c}{**Performance Criteria (\%)**} \\ \cline{5-10}  & & & & \multicolumn{3}{c}{**AD Vs. HC**} & \multicolumn{3}{c}{**MCI Vs. HC**} \\ \cline{5-10}  & & & & **AC** & **SE** & **SP** & **AUC** & **AC** & **SE** & **SP** & **AUC** \\ \hline \multirow{3}{*}{[208]} & Multitask feature selection & 51 AD + 99 MCI + & MRI & 91.10 & 91.57 & 92.88 & 96.55 & 73.54 & 81.01 & 65.38 & 78.26 \\  & method + MKL & 52 HC & FDG–PET & 91.02 & 89.02 & 90.58 & 95.84 & 72.08 & 75.56 & 59.23 & 77.06 \\  & method + MKL & 52 HC & MRI + FDG–PET & 94.37 & 94.71 & 94.04 & 97.24 & 78.80 & 84.85 & 67.06 & 82.84 \\ \hline \multirow{3}{*}{[188]} & Multivariate modeling + SVM & \multirow{3}{*}{50 MCI} & MRI & NA & NA & NA & 67 & 37 & 87 & NA \\  & & & FDG–PET & NA & NA & NA & NA & 62 & 10 & 97 & NA \\  & & & FIB–PET & NA & NA & NA & NA & 45 & 45 & 80 & NA \\  & & & MRI + FIB–PET & NA & NA & NA & NA & 76 & 53 & 90 & NA \\  & & & MRI + FDG–PET & NA & NA & NA & NA & 37 & 37 & 90 & NA \\ \hline \multirow{3}{*}{[184]} & Multimodal biomarker & \multirow{3}{*}{95 AD + 182 MCI} & MRI & 73 & NA & NA & 78 & 70 & NA & NA & 68 \\  & classifier + SVM & 95 AD + 111 HC & CSF & 82 & NA & NA & 85 & 74 & NA & NA & 77 \\  & & & MRI + CSF & 84 & NA & NA & 90 & 77 & NA & NA & 78 \\  & & MRI + CSF + ApoE & 85 & NA & NA & 88 & 79 & NA & NA & 79 \\ \hline \multirow{3}{*}{[187]} & MRI & \multirow{3}{*}{51 AD + 99 MCI + 52 HC} & MRI & 88.68 & 84.51 & 92.50 & 94 & 73.12 & 78.28 & 63.65 & 79 \\  & & & FDG–PET & 84.42 & 83.53 & 84.81 & 91 & 67.11 & 75.96 & 50.19 & 72 \\  & & CSF & 82.26 & 82.58 & 81.54 & 87 & 70.72 & 71.62 & 69.04 & 75 \\  & & MRI + FDG–PET & 95.00 & 94.90 & 95.00 & 97 & 79.27 & 85.86 & 66.64 & 82 \\  & & MRI + FDG–PET + CSF & 95.40 & 94.71 & 95.77 & 98 & 82.99 & 93.39 & 70.77 & 84 \\ \hline \multirow{3}{*}{[186]} & MKL with multitask & \multirow{3}{*}{51 AD + 99 MCI + feature learning} & MRI & 92.25 & 92.16 & 92.12 & 96 & 73.84 & 77.27 & 66.92 & 77 \\  & & & FDG–PET & 91.65 & 92.94 & 90.19 & 96 & 74.34 & 85.35 & 53.46 & 78 \\  & & MRI + FDG–PET & 95.95 & 95.10 & 96.54 & 97 & 80.26 & 84.95 & 70.77 & 81 \\ \hline \multirow{3}{*}{[209]} & M3 & 16 AD + 22 HC & MRI + PET & 89.47 & 87.5 & 90.91 & NA & NA & NA & NA \\ \hline \multirow{3}{*}{[210]} & \multirow{3}{*}{DNN} & 180 AD + 160 & MCI + 20 HC & MRI & 82.59 & 86.83 & 77.78 & NA & 71.98 & 49.52 & 84.31 & NA \\  & & & MRI + FDG–PET & 91.40 & 92.32 & 90.42 & NA & 82.10 & 60.00 & 92.32 & NA \\  & & & 77 HC & & & & & & & & \\ \hline \multirow{3}{*}{[211]} & CNN & 93 AD + 100 HC & MRI + PET & 89.64 & 87.1 & 92 & 94.45 & NA & NA & NA & NA \\ \hline \multirow{3}{*}{[17]} & \multirow{3}{*}{SVDD} & MRI & 88.15 & 89.02 & 90.18 & 95.00 & NA & NA & NA & NA \\  & & & FDG–PET & 85.16 & 86.84 & 84.14 & 92.04 & NA & NA & NA \\ \cline{1-1}  & & MRI + FDG–PET & 93.65 & 90.08 & 92.75 & 97.30 & NA & NA & NA & NA \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Cont._