Damage to the left ventral, arcuate fasciculus and superior longitudinal fasciculus-related pathways induces deficits in object naming, phonological language function and writing, respectively.

The anatomic localization of brain functions can be characterized via diffusion tensor imaging in patients with brain tumors and neurological symptoms. The goal of the present study was to evaluate the function of the ventral, arcuate fasciculus (AF) and the superior longitudinal fasciculus (SLF)-related language pathways using these techniques by analyzing 9 patients treated in our hospital between 2007 and 2011. In cases 1-3, the left ventral pathways, namely, the inferior longitudinal fasciculus, uncinate fasciculus or inferior fronto-occipital fasciculus, were mainly damaged, and the common dysfunction experienced by these patients was a deficit in object naming. In cases 4-6, the left SLF was mainly damaged, and the common deficit was dysgraphia. In cases 7-9, the left AF was mainly damaged, and almost all language functions related to phonology were abnormal. These results suggest that the left ventral, AF and SLF-related pathways are closely related to visual, auditory and hand-related language function, respectively.

Right temporal lobe plays a role in verbal memory.

OBJECTIVES: Comparison of preoperative and postoperative neurological functions in patients undergoing resection of brain tumors, in combination with data from diffusion tensor imaging (DTI) studies, can provide direct evidence of anatomical localization of brain function. The goal of the present study was to use these techniques to characterize memory function of the right temporal lobe in five patients with right temporal lobe brain tumors. METHODS: Memory function was tested using the Wechsler Memory Scale-Revised (WMS-R) before and after surgery in five patients with right temporal lobe brain tumors. Preoperative DTI was performed in four of five cases. RESULTS: In all cases, general and verbal memory, including verbal paired association, significantly improved after surgery (P<0.05). The right inferior longitudinal fasciculus (ILF) was compressed by the tumor in all cases. CONCLUSION: These results suggest that the right temporal lobe plays a role in verbal memory and that this function may be associated with the right ILF.

Damage to the upper portion of area 19 and the deep white matter in the left inferior parietal lobe, including the superior longitudinal fasciculus, results in alexia with agraphia.

Analysis of lesions and symptoms in patients with brain tumors combined with information from diffusion tensor imaging provides direct evidence of the anatomical localization of brain function. Using these methods, we evaluated 8 patients who underwent surgery for metastatic brain tumors located in the left occipital lobes between 2007 and 2009. Preoperatively, 4 patients (cases 1-4) had alexia with agraphia while the other 4 patients (cases 5-8) did not. Tractography for the superior longitudinal fasciculus (SLF) was performed before surgery in case 1. The common brain tumors in cases 1-4 were located in the upper portion of area 19, and peritumor edema in that area resulted in compromise of the deep white matter of the inferior parietal lobe (IPL). The SLF was compressed and disrupted in the white matter of the IPL near the upper portion of area 19 in case 1. In cases 5-8, the brain tumors were not located in the upper portion of area 19. These results suggest that damage to the upper portion of area 19 and to the white matter in the left IPL, including the SLF, resulted in alexia with agraphia.

Damage of left temporal lobe resulting in conversion of speech to Sutra, a Buddhist prayer stored in the right hemisphere.

The present study describes a case of a right-handed 74-year-old woman with a brain tumor who showed conversion of speech to Sutra, a Buddhist prayer, which was stored in the right hemisphere according to the Wada test. After surgery, relative improvement in the speech disorder was observed, and frequency of speech production of simple normal words with normal phonology increased. These observations indicate that damage to left temporal lobe resulted in conversion of speech to Sutra, and that Sutra was stored in this patient's right hemisphere.

Deficits in the left inferior longitudinal fasciculus results in impairments in object naming.

The functional characteristics of the left inferior longitudinal fasciculus (ILF) remain unclear. The present study describes a case of a right-handed 74-year-old woman with a brain tumor who showed marked deterioration in object naming ability after invasion of the tumor into the medial region of the left posterior (middle and inferior) temporal lobe just beside the atrium of the lateral ventricle. Diffusion tensor imaging showed possible interruption of the left ILF after invasion of tumor at this site. By contrast, the left superior longitudinal fasciculus (SLF) remained intact after invasion of tumor, and the inferior fronto-occipital fasciculus (IFOF) was already disrupted prior to tumor invasion. These observations indicate that intact ILF function may be required for object naming ability.

Impairment of inferior longitudinal fasciculus plays a role in visual memory disturbance.

Function of the inferior longitudinal fasciculus (ILF), which connects the anterior temporal and occipital lobes, has not been clearly demonstrated in the human brain. A 47-year-old woman with visual memory disturbance as demonstrated by the Wechsler Memory Scale-Revised presented with possible brain tumor in the right temporal lobe. Diffusion tensor imaging showed partial disconnection of the right ILF, indicating that function of the ILF is highly involved in visual memory.