Velasco_relayout_EU Neurology 08/03/2010 15:56 Page 90
Epilepsy
procedure itself. If MRI is normal, the outcome is worse. Velasco et after weeks and even months of continuous or cyclic stimulation. The
al.
20
investigated the anticonvulsive effect of cyclic, high-frequency field is immense.
stimulation of the epileptic foci located in the motor area in two
patients with non-lesional intractable epilepsy, one of them in the Multidisciplinary work is encouraged; neurologists, epileptologists,
right supplementary motor area and the other in the right primary neurophysiologists, neurosurgeons and neuropsychologists need
motor area. Both had 95% seizure reduction without motor function to interact and have close communication with basic scientists and
impairment. This result is very promising, although conclusions biomedical engineers. The latter have shown great interest and
cannot yet be drawn. texts are being elaborated in collaboration with neuromodulation
investigators.
1
Questions need to be answered, new targets and
No matter which target is stimulated, which parameters are used, different stimulation parameters need to be proposed, special
what results are reported or what disagreements exist, all authors electrode designs according to the stimulated target need to be
agree that neuromodulation is reversible and does not produce elaborated and smaller and less expensive stimulation systems that
adverse events. If somehow a patient presents an undesirable are better tolerated by patients need to be built.
effect, a change of stimulated contacts or parameters will eliminate
the problem. No adverse effects on neurological function have However, the field to be explored does not end with all this. A more
been observed; on the contrary, function, and thus quality of life, exciting phase is also being studied: the mechanisms that explain the
tends to improve. therapeutic effect of neuromodulation. Being able to modify the way
in which the brain works and to explain different circuits is intriguing.
Currently, there are many studies of therapeutic stimulation for It all guides us to the main field of interest of all neuroscientists: how
seizure control in progress. For example, detector systems are the brain works. n
implanted for temporal and extra-temporal epileptic foci. These
systems detect electroencephalography (EEG) activity to anticipate
Ana Luisa Velasco is Head of the Epilepsy Clinic of the Neurology and
changes related to seizure onset and are coupled to a stimulation
Neurosurgery Service at the General Hospital of Mexico City and a Professor at
system that delivers electric current through an electrode placed on the National Autonomous University of Mexico. She is a certified neurologist and
the epileptic zone. Initial reports are promising, although challenges
neurophysiologist and is a member of the National Research System. Dr Velasco
performed epilepsy training as an International Fogarty Fellow (NIH) at the Reed
remain since seizure anticipation may depend on EEG activities that
Neurological Research Center at the University of California, Los Angeles, has a
are not specific and therefore can provide false detections but, even PhD in medical sciences and obtained her MD at the Medical School at the
worse, can miss seizure onset. Besides, in all neuromodulation trials
National Autonomous University of Mexico.
it has been reported that the best anticonvulsive effects are reached
1. Brodie MJ, et al., Epilepsia, 1997;38:1245–50. 11. Fisher RS, et al., Epilepsia, 1992;33:841–51. 22. Velasco AL, et al., Arch Med Res, 2000;31:316–28.
2. Kwan P, Brodie M, N Engl J Med, 2000;342:314–9. 12. Velasco F, et al., Neurosurgery, 2000;47:295–305. 23. Velasco M, et al., Clin Neurophys, 2001;18:1–15.
3. Cooper IS, et al., Trans Am Neur Assoc, 1973;98:192–6. 13. Velasco AL, et al., Epilepsia, 2006;47:1203–12. 24. Cuellar-Herrera M, et al., Epilepsia, 2004;45:459–66.
4. Moruzzi G, Arch Fisiol, 1941;41:157–82. 14. Mirski MA, Fisher RS, Epilepsia, 1994;35:1309–16. 25. Velasco AL, et al., Epilepsia, 2007;48:1895–903.
5. Cooke PM, Snider RS, Epilepsia, 1955;4:19–28. 15. Kerrigan JF, et al., Epilepsia, 2004;45:346–54. 26. Vonck K, et al., Ann Neurol, 2002;52:556–65.
6. Davis R. In: Gildenberg P, Tasker RR (eds), Textbook of 16. Chabardes S, et al., Epileptic Disord, 2002;4(Suppl 3):S83–93. 27. Boon P, et al., Epilepsia, 2007;48:1543–50.
Stereotactic and Functional Neurosurgery, Houston: McGraw- 17. Vesper J, et al., Epilepsia, 2007;48:1984–9. 28. Tellez-Zenteno JF, et al., Neurology, 2006;66:1–5.
Hill, 1998:183–9. 18. Wiesser HG, et al. In: Engel J Jr (ed.), Surgical Treatment of the 29. Mihara T, et al., Adv Neurol, 1996;70:405–14.
7. Velasco F,et al., Epilepsia, 2005;46:1071–81. Epilepsies, New York: Raven Press, 1993:49–63. 30. Smith JR, King DW, Adv Neurol, 1996;70:41–427.
8. Ben-Menachem E,] Lancet Neurol, 2002;1:477–82. 19. Wiebe S, et al., N Engl J Med, 2001;345:311–8. 31. Engel J, et al. In: Engel J, ed., Surgical Treatment of the
9. Penfield W, Jasper H, Epilepsy and the functional anatomy of the 20. Velasco AL, et al., Textbook of Stereotactic and functional Epilepsies, 2nd edn., New York: Raven Press, 1993:609–21.
human brain, Boston: Little Brown, 1954:566–96. Neuosurgery, Berlin/Heidelberg (in press). 32. Olivier A, Adv Neurol, 1996;70:429–43.
10. Velasco F, et al., Epilepsia, 1987;28:421–30. 21. Weiss SR, et al.,Exp Neurol, 1998;154:185–92. 33. Spencer DD, Schumacher J, Adv Neurol, 1996;70:41–427.
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