Study of the localization of brain language areas started with findings obtained from patients with brain injury, however functional localization studies in epileptology began with findings on brain functional mapping using cortical electrical stimulation during brain surgery. Knowledge of language area identification and knowledge of language sequelae due to brain resection is essential for those engaged in epilepsy surgery. In recent years, many non-invasive examination and analysis methods have been developed, and it has become possible to carry out measurements on not only pathological brains such as epilepsy and cerebrovascular disease but also normal brains. In this educational lecture, I will introduce the language areas related to epilepsy treatment and actual brain functional mapping. In addition, recent findings on the language areas that are becoming clear by use of various examinations and analysis methods will be discussed, that is, the language areas related to vision, the language areas related to hearing, and the white matter tracts that connect cortical language areas. These language areas will be discussed together with some cases.
An 84-year-old man showed false recognition/misidentification of unfamiliar person after cardiogenic cerebral infarction. He was good in his vision and hearing acuity, without hemianopsia, unilateral spatial neglect and visual object agnosia, but he was unable to remember faces of his rehabilitation therapists, and repeatedly misidentifying other patients’ visitors and therapists as his family and friends, and he did not recognize these mistakes. General cognitive function was preserved with HDS-R 25/30 （cut-off score 20）. In terms of recognition of faces, tasks not requiring the recognition of facial identity, i.e. interpreting facial emotions, judging gender and age, were relatively preserved, but the recognition of family members and celebrities was severely and matching unfamiliar faces was slightly impaired. Family and friends’ semantic information’s were retained and resembled associative prosopagnosia, but his symptoms differed from general associative prosopagnosia in having phonagnosia. MRI lesions were localized not in the right occipital and temporal lobes, but in the frontal and temporal lobes including the right anterior temporal lobe, the pathological lesion of which is considered to cause multimodal people recognition disorders, with the inability of utilization of visual （face） and also auditory （voice） cues for person identification. In addition to this facial cognitive impairment, impaired exploratory （monitoring） function of the frontal lobe on the temporal lobe may also contribute to the false recognition/misidentification of this case.
Voxel-based specific regional analysis system for Alzheimer’s disease （VSRAD） is a new software program using magnetic resonance imaging （MRI） for the detection of early specific atrophy in Alzheimer’s disease （AD）. The target volume of interest （VOI） is the medial temporal region involving hippocampus, amygdala, and the entorhinal cortex. These regions, especially the hippocampus are concerned with memory function.
The purpose of this study was to assess whether there was a significant correlation between the severity score of atrophy in the target VOI and the Rivermead Behavioural Memory Test （RBMT） score that is a memory function test in everyday life scenes in the patients with early AD.
This study included 59 patients, and they were classified as FAST3 （borderline between normal and mild AD） or FAST4 （mild AD）. The Mini-Mental State Examination （MMSE） that is the most widely used screening tool for detecting dementia and a general cognitive function test, and the RBMT were administered to all patients. Out of the total patient pool, 32 patients were scanned with a 1.5Tesla MRI scanner and 27 patients were scanned with a 3Tesla MRI scanner. Their levels of medial temporal atrophy were then analyzed by VSRAD using the brain MRI data.
We found that there were more significant correlations between the severity score of atrophy in the target VOI and the RBMT score than the MMSE score.
These findings suggest that the RBMT is useful in detecting the early AD.