Research
Humans are capable of performing a large variation of movements and postures. The central nervous system (brain including spinal cord) controls the muscles, while using sensory feedback from e.g. muscle spindles and Golgi tendon organs.
The Neuromuscular Control Lab (NMC) focusses its research on understanding this complex control system. The main research fields are:
- Proprioceptive reflexes
- System identification
- Movement disorders
- Neural modelling
- Driver assistance
Proprioceptive reflexes
Afferent feedback plays an important role in human motor control. The dynamics of a human joint comprise inertial and visco-elastic properties of passive tissues and muscles, as well as reflexes resulting from afferent feedback. During postural control, reflexive stiffness can make up to half of the total joint stiffness.
Continuous random force disturbances have proven to be useful to quantify spinal reflexes and such to assess the functionality of reflexes. Force perturbations represent a natural form of input and mimic most real life situations: the subject can actively control the position and must preserve stability in the presence of external (force) disturbances.
The force disturbances require special force controlled robotic manipulators. At the NMC Lab, several manipulators have been developed to asses reflexes in the wrist, shoulder and ankle (see also Laboratory).
System identification
Methods are being developed to quantify proprioceptive reflex strengths during human posture and movement. Using robot manipulators the position and/or motion of patients is perturbed, and the response measured. From these measurements the reflexive strength settings in the spinal cord can be identified.
Movement disorders
Some neural disorders, like Parkinson's disease and Complex Regional Pain Syndrome affect proprioceptive reflexes. At NMC, we apply identification and modelling techniques to neural disorders, in order to aid the diagnosis of these diseases and to gain insight in their underlying mechanisms.
Neural modelling
The human reflex system is modelled in a detailed, biologically realistic way, using biological neural networks, sensory models and models of the human musculoskeletal system. On this level of detail, relationships can be laid between neural processes and the observed behaviour. This will not only enable us to increase knowledge on workings of the CNS itself, but it will also provide insight in the neural causes and mechanisms of the motoric disorders, with a focus on complex regional pain syndrome (CRPS).
Driver assistance
A driver support system was developed, which helps drivers in enhancing their awareness of the environment and in supporting them to properly allocate their attentional resources. The focus of the NMC Lab was to investigate the possibilities and limitations of providing continuous haptic feedback on the gaspedal to inform drivers of hazards in front of their car.