Lesion-Specific Language Network Alterations in Temporal Lobe Epilepsy

BACKGROUND AND PURPOSE

Temporal lobe epilepsy, structural or nonlesional, may negatively affect language function. However, little is known about the lesion-specific influence on language networks. We hypothesized that different epileptogenic lesions are related to distinct alterations in the functional language connectome detected by fMRI.

MATERIALS AND METHODS

One hundred one patients with epilepsy due to mesiotemporal sclerosis (21 left, 22 right), low-grade mesiotemporal tumors (12 left), or nonlesional temporal lobe epilepsy (22 left, 24 right) and 22 healthy subjects performed 3T task-based language fMRI. Task-based activation maps (laterality indices) and functional connectivity analysis (global and connectivity strengths between language areas) were correlated with language scores.

RESULTS

Laterality indices based on fMRI activation maps failed to discriminate among patient groups. Functional connectivity analysis revealed the most extended language network alterations in left mesiotemporal sclerosis (involving the left temporal pole, left inferior frontal gyrus, and bilateral premotor areas). The other patient groups showed less extended but also predominantly ipsilesional network changes compared with healthy controls. Left-to-right hippocampal connectivity strength correlated positively with naming function (P = .01), and connectivity strength between the left Wernicke area and the left hippocampus was linked to verbal fluency scores (P = .01) across all groups.

CONCLUSIONS

Different pathologies underlying temporal lobe epilepsy are related to distinct alterations of the functional language connectome visualized by fMRI functional connectivity analysis. Network analysis allows new insights into language organization and provides possible imaging biomarkers for language function. These imaging findings emphasize the importance of a personalized treatment strategy in patients with epilepsy.

[Identifying language and communication disorders as part of the medical curriculum]

BACKGROUND

Like hearing loss, language and speech disorders can also lead to impaired communication. Speech and language disorders can occur at any age, for example as a specific language impairment, stuttering, dysarthria, and aphasia. Hence, irrespective of their speciality, there is a high probability that physicians will at some point encounter communication-impaired patients, be required to classify their disorder and refer them for appropriate therapy.

METHODS

A new module entitled 'communication disorders' consisting of two teaching units was integrated in the practical course 'ENT--phoniatrics--pedaudiology' for undergraduate clinical students in 2008. The learning objective of the first unit was to identify and classify communication disorders, presented using sound and video data, by means of simple criteria. The module was evaluated on the basis of questionnaires completed by 164 students.

RESULTS

On a scale of 1-7, the evaluation showed overall positive results with 6.54 (highest score) for professional competence and 5.32 (lowest score) for discussion. The overall score was 12.28 out of a possible maximum of 15 points.

CONCLUSION

The ability to identify communication impairments is an important medical skill. Since communication disorders are common diseases we suggest that this skill be incorporated in the medical curriculum. Thus we have introduced a module for communication disorders; its evaluation by students shows a high level of satisfaction in each category. After developing specific diagnostic indicators students were able to independently describe and identify communication disorders.