Clinical Neurophysiology

EEG rhythms

Although the EEG is almost over 100-years old, the processes that are ultimately responsible for the rhythms that can be recorded on the brain surface of skull are only partially understood. Part of the research focuses on elementary issues related to EEG generation and interpretation.[1,2]

Part of an EEG

Figure 1: Part of an EEG. The subject closes his eyes at the dotted line, resulting in the emergence of the alpha rhythm.

ICU & OR Monitoring

Monitoring of Brain Function of high-risk patients in the Intensive Care Unit (ICU) is still limited. Although the EEG is a potentially very useful technique for real-time monitoring, at present this is not routine use in the ICU. Limitations include mounting time and the visual burden for the interpretation. An example of a visual transform is shown in figure 2.[2]

Visual transform of an EEG

Figure 2: The Colorful Brain: A visual transform of the EEG.

Several of these techniques are currently implemented in our ICU for further clinical evaluation. Ischaemie in the operating room (OR) may occur during carotid surgery. A few years ago, I proposed The Brain Symmetry Index (BSI) to assist in the decision to shunt or not to shunt in carotid endarterectomy.[3,4] In the meantime, this index has proven very relevant for monitoring stroke patients, as well. [5]


Epilepsy is a very common neurological disease (incidence about 1%). The diagnostic process in epilepsy is still faced with many challenges, in particular to make a reliable estimate of seizure recurrence. At this moment a research project, initiated by Advanced NeuroTechnology (ANT), combining TMS and EEG, is focusing on this question.

Sometimes, remarkable phenomena can be observed in patients suffering epilepsy.[6]

Stroke & Ischaemia

Very recently, the University of Twente, University Medical Center Nijmegen, the Donders Institute Nijmegen, Siemens and two companies in Enschede (ANT and TMSi) obtained a 2.3 MEuro grant for research related stroke and ischaemia. This project, entitled VIP Brain-Networks includes the search for (novel) risk factors, and innovative strategies for rehabilitation.  

Pain & Neuromodulation

Treatment of chronic pain is often difficult. Recently, at the MST, patients with diabetic neuropathy are treated with neuromodulation (spinal cord stimulation). Initial results look very promising. At the same time the potential working mechanism of spinal cord stimulation is investigated. More details can be found at the department of Neurosurgery of the MST.

Relevant Literature

1.M.J.A.M. Van Putten and C.J. Stam, Application of a neural complexity measure to multichannel EEG, Phys Letters A 281(2-3): 131-141, 2001.

2.M.J.A.M. van Putten, The colorful brain: Visualization of EEG background patterns, J Clin Neurophysiol, 25(2):63-68, 2008.

3.M.J.A.M. van Putten, J.M. Peters, S.M. Mulder, J.A.M. de Haas, C.M.A. Bruijninckx and D.L.J. Tavy, A brain symmetry index (BSI) for online EEG monitoring in carotid endarterectomy, J Clin Neurophysiol 115(5): 1189-1194, 2004.

4.M.J.A.M. van Putten, The revised Brain Symmetry Index, J Clin Neurophysiol 118(11): 2362-2367, 2007.

5.M.J.A.M. van Putten and D.L.J. Tavy, Continuous quantitative EEG monitoring in hemispheric stroke patients using the Brain Symmetry Index, Stroke 35(11): 2489-2492, 2004.

6.M.J.A.M. van Putten and M.H.P.M. van Putten, Discovery of recurrent multiple brain states in non-convulsive status epilepticus. J Clin Neurophysiol, 118(12): 2798-2804, 2007.