People with epilepsy often display cognitive decline. Language function in epilepsy has been most thoroughly studied in temporal lobe epilepsy, but the impact of language deficits in epilepsy is not fully understood. The aim of this study was to evaluate the effect of epilepsy on language function with functional magnetic resonance imaging of brain activation, with behavioral methods and to relate language performance to demographic data, self-esteem and Quality of life. We specifically aimed to investigate if variation in epilepsy origin would relate to differences in language performance and if these differences could be associated with specific language activation patterns in the brain. We recruited people with epilepsy (29 in total), with focal onset seizures in either the left or right hemispheres or with generalized epilepsy; and 27 matching healthy controls. The participants’ language skills were measured with a phonemic word fluency test and a broader test measuring higher language functions. Functional magnetic resonance images of the brain were obtained during a word fluency and a sentence reading paradigm. Questionnaires on self-esteem and quality of life were collected. People with epilepsy of both focal and generalized origin had impaired function in semantic and verbal fluency tasks compared to the controls. The causes of language impairment were multifactorial; the most important determinants were education and onset age of epilepsy. Impaired language function was correlated to low self-esteem for participants with focal onset seizures; however Quality of life did not seem to be affected by language impairment. The functional magnetic resonance imaging investigation demonstrated altered functional activity during language tasks for participants with epilepsy compared to healthy controls. In epilepsy with focal seizures originating in the left hemisphere we found increased bilateral  activation of supporting areas in the anterior mid-cingulate cortex and the left anterior ventral insula, indicating a compensational functional reorganization. In generalized epilepsy, the functional language network showed an imbalance expressed as an inadequate  suppression of activation in the left anterior temporal lobe during semantic processing. Our study shows not only that reduced language functioning is present in people with epilepsy other than in the temporal lobe, but also that frequency of convulsive seizures correlates to language impairment. For patients with focalized seizures, low self esteem correlated also to language impairment. Our results highlight the importance of addressing the negative consequences of language decline in people with epilepsy of both focal and generalized origin.

Cell therapy aiming at the replacement of degenerated neurons is a very attractive approach. By using an established in vitro organotypic brain stem (BS) slice culture we screen for candidate donor cells, some of them being further functionally assessed in in vivo models of sensorineural hearing loss. Both in vitro and in vivo systems show that implanted cells face challenges of survival, targeted migration, differentiation and functional integration with the host tissue. Low success rates are possibly due to the lack of necessary neurotrophic factors, adhesion molecules and guiding cues. Olfactory ensheathing cells (OECs) have been shown to express a number of neurotrophic factors and to promote axonal growth through cell to cell interactions. In the present study we co-cultured OECs with organotypic BS slice in order to see if OECs can serve as a facilitator when screening candidate donor cells in an organotypic culture setup. Here we show that OECs when co-cultured with the auditory BS slice not only promote neurite outgrowth from the cochlear nucleus (CN) region of the BS slice but also support cells by having BS slice axons growing along their processes. These findings further suggest that OECs may enhance survival and targeted migration of candidate donor cells suitable for cell therapy in vitro and in vivo. This article is part of a Special Issue entitled: Understanding olfactory ensheathing glia and their prospect for nervous system repair.

At present severe damage to hair cells and sensory neurons in the inner ear results in non-treatable auditory disorders. Cell implantation is a potential treatment for various neurological disorders and has already been used in clinical practice. In the inner ear, delivery of therapeutic substances including neurotrophic factors and stem cells provide strategies that in the future may ameliorate or restore hearing impairment. In order to describe a surgical auditory nerve trunk approach, in the present paper we injected the neuronal tracer horseradish peroxidase (HRP) into the central part of the nerve by an intra cranial approach. We further evaluated the applicability of the present approach by implanting statoacoustic ganglion (SAG) cells into the same location of the auditory nerve in normal hearing rats or animals deafened by application of p-bungarotoxin to the round window niche. The HRP results illustrate labeling in the cochlear nucleus in the brain stem as well as peripherally in the spiral ganglion neurons in the cochlea. The transplanted SAGs were observed within the auditory nerve trunk but no more peripheral than the CNS-PNS transitional zone. Interestingly, the auditory nerve injection did not impair auditory function, as evidenced by the auditory brainstem response. The present findings illustrate that an auditory nerve trunk approach may well access the entire auditory nerve and does not compromise auditory function. We suggest that such an approach might compose a suitable route for cell transplantation into this sensory cranial nerve.