# Perspectives and Challenges in Robotic Neurorehabilitation
## 2 An Overview of Robotic Devices for Neurorehabilitation
### Robotic Neurorehabilitation for the Upper Limb
Finally, the T-Wrex [68] and its commercial version, ARMEO Spring (Hocoma, Switzerland), only provide gravity support to the whole arm with no robotic actuation [69]. Upper limb exoskeletons for rehabilitation have been developed only recently compared to the end-effector devices. This is due to different reasons [70]: (i) The complex interaction between the mechanical structure of the exoskeletons and the different joints of the human body; (ii) the complex control schemes to be adopted to deal with back-drivability and transparency; and (iii) the need to \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Exoskeleton** & & & & & \\
**Name and** & **Actuators** & **Actuated DOFs** & **Training** & **Trigger Event for** & **Type of** \\
**Reference** & & & & & \\ \hline \multirow{4}{*}{SUEFUL7 [49]} & \multirow{4}{*}{Electric} & Shoulder vertical and horizontal & & & \\  & & flex,/ext; shoulder internal/external & & & \\  & & rot; elbow flex,/ext; forearm & & & \\  & & sup;/pron; wrist flex/ext;, and wrist & & & \\  & & radial/ulnar dev. & & & \\ \hline \multirow{4}{*}{ARMin III [50]} & \multirow{4}{*}{Electric} & Shoulder joint in three DOFs; elbow flex,/ext; lower arm pron/sup; and wrist flex/ext. & Active; Passive; Active & Assist-as-needed strategy based on & Stroke [57]; SCI [58]; other \\  & & & wrist flex/ext. & & & \\  & & & & & \\  & & & & & \\ \hline \multirow{4}{*}{CADEN [51]} & Electric & Shoulder flex,/ext; abd,/add;; & & & \\  & (Brushed & internal/external rot; elbow flex/ext; & Active; Passive & - & - \\  & motors—Cable & forearm sup;/pron.; wrist flex/ext; & Passive & & \\  & drive) & and radial/ulnar dev. & & & \\ \hline \multirow{4}{*}{RUPERT [52]} & \multirow{4}{*}{Pneumatic} & Shoulder flex,/ext;; human & & & Movement trajectory & \\  & & internal/external rot; elbow flex/ext; & & & \\  & & forearm pron/sup; and wrist & & & \\  & & flex,ext. & & & \\ \hline \multirow{2}{*}{L-Exos [54]} & \multirow{2}{*}{Electric} & Shoulder abd,/add.; elbow flex,/ext; wrist pron/sup. & Active; Passive & - & Stroke [60] \\ \hline \multirow{4}{*}{UL-Exo7 [51]} & \multirow{4}{*}{Electric} & Shoulder flex,/ext; shoulder & & & \\  & & abd,/add;; shoulder internal–external & & & \\  & & rot; elbow flex/ext; forearm rot.; & Active & & \\  & & wrist flex/ext; and wrist & & & \\  & & radial–ulnar dev. & & & \\ \hline \multirow{4}{*}{Pneu-Wrex [63]} & \multirow{4}{*}{Pneumatic} & Forward/backward clavicle rot.; shoulder & Passive; Active; Active & Assistance-as-needed strategy based on & Stroke [55] \\  & & horizontal abd,/add.; and elbow & Active & & \\  & & flex,/ext. & & & \\ \hline \multirow{4}{*}{IntelliArm [64]} & \multirow{4}{*}{Electric} & Shoulder abd,/add.; flex/ext.; internal/external rot.; elbow flex/ext, & Passive; Active; Active & & \\  & & and forearm sup;/pron.; wrist flex,/ext; hand open/grasp at MCP & Active & & \\  & & and thumb joints. & & & \\  & & & Resistive & & \\ \hline \multirow{4}{*}{BONES [65]} & \multirow{4}{*}{Pneumatic} & Shoulder abd,/add.; flex/ext.; internal/external rot.; elbow flex,/ext. & Passive; Active & Assist-as-needed strategy based on & Stroke [65] \\  & & & internal/external rot.; elbow flex,/ext. & Assistive & \\ \hline \multirow{4}{*}{MCP: metacarpophalangeal joint; Flex. Flexion; Ext. Extension; Sup. Supination; Pron. Pron. Pronation; Dev. Deviation; Rot. Rotation; Abd. Abduction; Add. Adduction. Abbreviations for diseases under examination—SCI: Spinal Cord Injury.} & \multirow{4}{*}{Stroke [65]} \\  & & & Passive; & Assist-as-needed strategy based on & \\ \cline{1-1}  & & & Active & & \\ \cline{1-1}  & & Active & & & \\ \cline{1-1}  & & Active & & & \\ \cline{1-1}  & & Active & & & \\ \hline \end{tabular}
\end{table} 
Table 2: Main features of the most common upper limbs exoskeletons. promote sensorimotor recovery of the patient not passively moving their joints but using assistive training modalities able to respond to any pathological movement [71].