Nobusada Shinoura

Fibers connecting the primary motor and sensory areas play a role in grasp stability of the hand.

The goal of this study was to evaluate the function of fibers that connect the hand area of the primary motor and sensory cortices. A 63-year-old male with a metastatic brain tumor located in the left primary motor area underwent awake surgery. During removal of the tumor, the posterior end of the primary motor cortex, including the fibers between the motor and sensory cortex, was resected, as confirmed by 3D reconstruction of fMRI and diffusion tensor imaging (DTI). Preoperative fMRI with right hand clenching revealed activation in the area around the tumor in the primary motor area. Postoperative fMRI with right hand clenching showed posterior shift of the activation to the sensory area. In contrast, 3D reconstruction of fMRI and DTI with left hand clenching showed activation of cortex corresponding to the motor and sensory hand area. Postoperative neurological examination revealed no change in right hand strength, but the patient complained of decrease right hand grasp stability when he concentrated on using his left hand. These findings suggest that the fibers connecting the primary hand motor and sensory areas play a role in the hand grasp stability.

Decreased vasoreactivity to right cerebral hemisphere pressure in migraine without aura: a near-infrared spectroscopy study

OBJECTIVEnSeveral studies have reported changes in cerebrovascular reactivity during the interictal period of migraine. To characterize mechanisms of migraine, we compared changes in total haemoglobin (THbl) and regional oxygen saturation (rSO(2)) of the right and left frontal lobes in response to intracranial pressure changes during the interictal period of migraine.nnnMETHODSnTwelve right-handed migraineurs without aura and twelve age- and sex-matched healthy volunteers were asked to perform a head-down maneuver to increase intracranial venous pressure. Initial THbl was designated as 1.0, and all subsequent THbl measurements, which was proportional to the change in cerebral blood flow, were expressed as a value relative to this baseline.nnnRESULTSnThe head-down maneuver resulted in a significantly smaller increase in right-sided THbl in migraineurs when compared to volunteers (migraineurs, -0.1+/-0.04; volunteers, 30+/-13; P=0.027), but there was no significant difference in left-sided THbl when comparing migraineurs and volunteers. Further, the head-down maneuver produced a significantly smaller increase in right-sided THbl than in left-sided THbl in migraineurs (right side, -0.1+/-0.04; left side, 0.35+/-0.08; P<0.0001), but produced a significantly greater increase in right-sided THbl than in left-sided THbl in volunteers (right side, 30+/-13; left side, 0.44+/-0.13; P=0.030). The head-down maneuver resulted in a smaller decrease in right-sided rSO(2) in migraineurs when compared to volunteers (migraineurs, -4.1+/-2.2%; volunteers, -16+/-9.1%), but produced a significantly greater decrease in left-sided rSO(2) in migraineurs when compared to volunteers (migraineurs, -1.3+/-1.1%; volunteers, 2.8+/-0.63%; P=0.0037).nnnCONCLUSIONSnThese data indicate that pressure-related vasoreactivity is suppressed in the right hemisphere of migraineurs during the interictal period.nnnSIGNIFICANCEnThe suppression of vasoreactivity in the right hemisphere might be related to the pathogenesis of migraine.

Awake craniotomy for brain lesions within and near the primary motor area: A retrospective analysis of factors associated with worsened paresis in 102 consecutive patients.

Background: We analyzed factors associated with worsened paresis in a large series of patients with brain lesions located within or near the primary motor area (M1) to establish protocols for safe, awake craniotomy of eloquent lesions. Methods: We studied patients with brain lesions involving M1, the premotor area (PMA) and the primary sensory area (S1), who underwent awake craniotomy (n = 102). In addition to evaluating paresis before, during, and one month after surgery, the following parameters were analyzed: Intraoperative complications; success or failure of awake surgery; tumor type (A or B), tumor location, tumor histology, tumor size, and completeness of resection. Results: Worsened paresis at one month of follow-up was significantly associated with failure of awake surgery, intraoperative complications and worsened paresis immediately after surgery, which in turn was significantly associated with intraoperative worsening of paresis. Intraoperative worsening of paresis was significantly related to preoperative paresis, type A tumor (motor tract running in close proximity to and compressed by the tumor), tumor location within or including M1 and partial removal (PR) of the tumor. Conclusions: Successful awake surgery and prevention of deterioration of paresis immediately after surgery without intraoperative complications may help prevent worsening of paresis at one month. Factors associated with intraoperative worsening of paresis were preoperative motor deficit, type A and tumor location in M1, possibly leading to PR of the tumor.

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.

Damage to the right dorsal anterior cingulate cortex induces panic disorder

Brain imaging studies suggest that panic disorder (PD) is mediated by several brain regions, including the anterior cingulate cortex (ACC). In the present report we describe a patient who experienced a panic attack during awake surgery (case 1) and another patient who developed PD after surgery and radiotherapy (case 2). In case 1, the patient experienced repeated panic attacks when the tumor at the upper border of right dorsal ACC was removed during awake surgery. In case 2, the patient developed PD at six months after surgery and Cyberknife radiotherapy. MRI examination revealed that the dorsal ACC size was reduced at six months after surgery and that the dorsal ACC was absent at two years after surgery, possibly due to radiotherapy-induced damage by radiotherapy. Profile of mood states (POMS) testing characterized the presence of tension-anxiety as the common abnormal symptom in cases 1 and 2. In conclusion, these results suggest that damage to the right dorsal ACC can induce PD and that this structure likely plays a pathophysiologic role in PD.

Right temporal lobe plays a role in verbal memory

Abstract 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.

The right dorsal anterior cingulate cortex may play a role in anxiety disorder and visual function

Abstract Recent investigation suggests that the dorsal anterior cingulate cortex (ACC) is involved in the interplay between cognition and emotion. The present study described three patients who underwent removal of brain tumors just above the right dorsal ACC. These patients had residual tumor following surgery and showed anxiety disorder (AD) both before and after surgery. Visual memory or attention was abnormal before surgery in these patients, but these deficits improved following surgery, possibly due to a decrease in compression of the right dorsal ACC. These results suggest that damage to the right dorsal ACC is involved in AD and well as in deficits in visual memory or attention. Therefore, the right dorsal ACC might play a role in vision-related cognition and emotion, such as anxiety.

Dizziness is associated with decreased vasoreactivity in right cerebral hemisphere for head-down manoeuvre--near-infrared spectroscopy study.

To investigate the vasoreactivity of cerebral hemisphere in patients with dizziness and syncope, we compared changes in total haemoglobin (THbl) and regional oxygen saturation (rSO2) of the right and left frontal lobes in response to head‐down manoeuvre. Ninety‐six right‐handed subjects (aged 59u2003±u200319u2003years) were asked to perform a head‐down or a standing manoeuvre. Head‐down manoeuvre produced a greater increase in right side THbl in subjects under 70u2003years of age (8·5u2003±u20033·1) when compared with subjects older than 70u2003years (0·40u2003±u20030·08). In contrast, the head‐down manoeuvre had no effects on left side THbl, irrespective of patient age. Similarly, the head‐down manoeuvre resulted in a greater decrease of right side rSO2 in subjects under 70u2003years of age (−5·2u2003±u20032·1%) when compared with subjects older than 70u2003years (0·31u2003±u20030·9%). In contrast, the head‐down manoeuvre had no effects on left side rSO2, irrespective of patient age. The head‐down manoeuvre produced a smaller increase in right side THbl in subjects with dizziness (0·38u2003±u20030·19) than in those without dizziness (9·4u2003±u20033·5). A standing manoeuvre produced a smaller increase in right side THbl in subjects with syncope (−0·057u2003±u20030·047) than in those without syncope (0·063u2003±u20030·028). The head‐down manoeuvre produced a decrease in right side rSO2 in subjects without dizziness (−6·4u2003±u20032·4%) and a slight increase in right side rSO2 in subjects with dizziness (1·1u2003±u20030·4%). Subjects with dizziness (67u2003±u20032·1u2003years) were significantly older than those without dizziness (53u2003±u20032·7u2003years) or those with syncope (44u2003±u20034·2u2003years). These data indicate that reduced vasoreactivity to right hemispheric pressure changes is associated with dizziness in older subjects. Further, decreases in right hemispheric THbl during a standing manoeuvre are associated with syncope in relatively younger subjects.

Preservation of hearing following awake surgery via the retrosigmoid approach for vestibular schwannomas in eight consecutive patients

BackgroundHearing preservation in patients with vestibular schwannomas remains difficult by microsurgery or radiosurgery.MethodIn this study, awake surgery via the retrosigmoid approach was performed for vestibular schwannomas (volume, 11.6xa0±xa011.2xa0ml; range, 1.3–26.4xa0ml) in eight consecutive patients with preoperative quartering of pure tone audiometry (PTA) of 53xa0±xa027xa0dB.ResultsAfter surgery, hearing was preserved in seven patients and improved in one patient. The postoperative quartering PTA was 51xa0±xa021xa0dB. Serviceable hearing (class Axa0+xa0Bxa0+xa0C) using the American Association of Otolaryngology-Head and Neck Surgery (AAO-HNS) classification was preserved in all patients. Preoperative useful hearing (AAO-HNS class Axa0+xa0B) was observed in three patients, and useful hearing was preserved in all three of these patients after surgery. In addition, useful facial nerve function (House-Blackmann Grade 1) was preserved in all patients.ConclusionsThese results suggest that awake surgery for vestibular schwannomas is associated with low patient morbidity, including with respect to hearing and facial nerve function.

The Left Superior Longitudinal Fasciculus within the Primary Sensory Area of Inferior Parietal Lobe Plays a Role in Dysgraphia of Kana Omission within Sentences

Functional neurological changes after surgery combined with diffusion tensor imaging (DTI) tractography can directly provide evidence of anatomical localization of brain function. Using these techniques, a patient with dysgraphia before surgery was analyzed at our hospital in 2011. The patient showed omission of kana within sentences before surgery, which improved after surgery. The brain tumor was relatively small and was located within the primary sensory area (S1) of the inferior parietal lobe (IPL). DTI tractography before surgery revealed compression of the branch of the superior longitudinal fasciculus (SLF) by the brain tumor. These results suggest that the left SLF within the S1 of IPL plays a role in the development of dysgraphia of kana omission within sentences.