Assess the ability of non-communicating patients to understand the meaning of words by measuring their brain activity is the winning bet of Lionel Naccache’s team.
The method seems to be simple : researchers make patients in a vegetative or minimal conscious state, listen to two words having a link between each other (hive-bee, or sledge-snow, for example) or not (hive-snow or sledge-bee). When there is no link between words, researchers report two particular responses at the level of patients’ brain activity : the first one occurs unconsciously, while the second one seems to be related to the awareness of sense.
This discovery highlights the existence of an unconscious stage in understanding the meaning of words which can be followed, or not, by a conscious step.
Patients in whom researchers have observed the two types of responses have recovered both consciousness and language after six months.
In light of these very encouraging results, Lionel Naccache’s team is currently optimizing this assay to predict not only consciousness recovery, but also cognitive abilities recovery in non-communicating patients.
Reference : Rohaut B, et al.Probing ERP correlates of verbal semantic processing in patients with impaired consciousness. Neuropsychologia. 2015 Jan;66:279-92. doi: 10.1016/j.neuropsychologia.2014.10.014.