# Perspectives and Challenges in Robotic Neurorehabilitation
## 3 Current Trends of Robot-Aided Neurorehabilitation
### Multimodal Assessment of Recovery
#### 3.2.2 Quantitative Assessment of the Sensorimotor Performance  
Recent advancements in haptic interfaces designed for sensorimotor rehabilitation provided the starting point for an innovative robot-aided assessment. In fact, such a technology is provided with high temporal and spatial resolution measurement systems that allow precise and continuous measurement of the positions, velocities, and forces of the joints and obtain kinematic and kinetic parameters from them [187; 188]. These features of robotic technologies for rehabilitation allow the collection of large normative data sets through a reliable procedure that yields objective, reliable data at a high resolution. Recent contributions highlight the efficacy of robotic devices in providing meaningful information on sensorimotor functions for neurological subjects [189]. These measurements are objective and repeatable and can be used to provide patients and therapists with immediate measures of sensory and motor performance. Reducing the time to evaluate improvement or deterioration may offer new opportunities for designing therapeutic programs and ultimately for increasing the efficiency of patients' care.  
It is worth highlighting how robotic devices can instantaneously measure subjects' performance during the whole treatment process, providing online indirect movement evaluation, making the assessment transparent to the patient, and reducing/eliminating the administration time as they can offer therapists and patients immediate feedback. Real-time scoring can not only greatly reduce the amount of time required for evaluations of patients' motor improvements, but it is also becoming a key need for new robot-aided neurorehabilitation scenarios.  
Recently, new ways have emerged to even assess energy consumption and psychological states by coupling robot sensors and external devices. Energy consumption, for example, is really relevant during walking and, in order to minimize it, humans are able to change the step length, arm swing, and cadence [190]. It is well known that neurological diseases affecting gait increase energy expenditure up to 70% with respect to healthy conditions [191]. This issue has been quantitatively assessed using indirect calorimetry while patients were walking wearing an exoskeleton [192]. Moreover, new assessment methods that use modelling and only robot sensing capabilities are under development [193]. Regarding the possibility to assess psychological states, there are many studies in the human-robot interaction field [194; 195; 196]. In particular, the assessment of these states could be crucial to quantitatively monitoring the level of engagement and motivation of the patients. This can be done using external devices to measure heart rate variability, breathing frequency, skin conductance response, and skin temperature and correlating these measures with kinematic and dynamic information coming from the robot [197].  
To conclude, robotic devices designed for neurorehabilitation might improve the quality of quantitative assessment, which is also essential to better understand and infer the rehabilitation treatment effect on sensorimotor function. Robotic measurements can potentially outperform human-administered clinical scales and are only limited by the performance of the robot sensors.