Traumatic head injury not only can result in immediate seizures, it often causes chronic seizures which are frequently resistant both to medication and surgical intervention. For these cases, local cooling of the brain has been investigated both as a way to short-circuit seizure activity once it has begun, or even prevent them from happening together. A group of physician researchers at Washington University in St. Louis have built a new device capable of cooling the brain of a rat while monitoring it for the electric signatures of seizures. In preparation for porting this technology to humans, they have begun formalization of a rigorous procedure fit for the operating room.
From the picture of the device alone it is not clear whether the cooling is done by passively radiating to the surroundings or whether the fittings shown might indicate that a cold liquid is pumped through the device. Either method would probably involve considerable bulk. In other words not the kind of thing you might walk around with in seizure-free bliss. The researchers found that just a 2 degree (Celsius) drop in local temperature was enough to scuttle off seizures. Often these types of studies are done using engineered animals bearing genes that make them susceptible to seizures. Since the potential outcome in these studies is intimately driven by the particular etiology (cause and circumstance) of the seizure, the researchers used mice that had been given lesions that mimic the injury frequently encountered in head trauma.
The researchers did not report direct behavioral studies that might give some indication as to what the rats thought about all this, in particular, how they might perform on a memory test. They did, however, do a general post-mortem pathophysiological assessment of inflammatory gene expression in the brain and reported no additional insults over controls.
Cooling a brain is easier said than done, and for the longer term more portable methods of brain cooling would be necessary. Other researchers have investigated more compact and “active” methods that take advantage of the thermoelectric properties of a Peltzier array. These arrays are used nowadays to cool computer chips and can be made extremely tiny. The problem is that while one side gets very cold, the other side gets very hot, and typically needs to be expanded to form a heat sink to conduct excess heat away.
A recent speculative paper by this author has suggested that intraventricular Peltier arrays placed below the corpus callosum might be used to perform, in effect, a reversible “safe-mode boot” of the brain into a partial split-brain situation. The split-brain procedure is typically a radical, last-resort procedure to address severe epilepsy. A reversible procedure to test the possible efficacy of the full surgery would be a welcome development. Further investigation would be needed to explore the possibility of exhausting excess heat directly to the CSF, or perhaps to the venous drainage.
Study abstract in Annals of Neurology: Mild passive focal cooling prevents epileptic seizures after head injury in rats
Press release: Cooling may prevent trauma-induced epilepsy
