Maiko Sakamoto

Sex differences in spatial object-location memory in a virtual grocery store.

The grocery shopping Virtual Reality Spatial Object-Location Test (VRSOLT) was developed to examine sex differences in spatial object-location memory in a 3D virtual environment that simulates the real world. Forty college students (20 males, 20 females) were tested on the VRSOLT as well as mental rotation and 2D object-location memory tasks. Both convergent and divergent validity was demonstrated. Males showed an advantage on mental rotation, and results of the VRSOLT grocery store test replicated the female object-location advantage seen in 2D tests. A strategy of systematically navigating the environment may aid female encoding for object location.

Sex and Cultural Differences in Spatial Performance Between Japanese and North Americans

Previous studies have suggested that Asians perform better than North Americans on spatial tasks but show smaller sex differences. In this study, we evaluated the relationship between long-term experience with a pictorial written language and spatial performance. It was hypothesized that native Japanese Kanji (a complex pictorial written language) educated adults would show smaller sex differences on spatial tasks than Japanese Americans or North Americans without Kanji education. A total of 80 young healthy participants (20 native Japanese speakers, 20 Japanese Americans-non Japanese speaking, and 40 North Americans-non Japanese speaking) completed the Rey Complex Figure Test (RCFT), the Mental Rotations Test (MRT), and customized 2D and 3D spatial object location memory tests. As predicted, main effects revealed men performed better on the MRT and RCFT and women performed better on the spatial object location memory tests. Also, as predicted, native Japanese performed better on all tests than the other groups. In contrast to the other groups, native Japanese showed a decreased magnitude of sex differences on aspects of the RCFT (immediate and delayed recall) and no significant sex difference on the efficiency of the strategy used to copy and encode the RCFT figure. This study lends support to the idea that intensive experience over time with a pictorial written language (i.e., Japanese Kanji) may contribute to increased spatial performance on some spatial tasks as well as diminish sex differences in performance on tasks that most resemble Kanji.

Greater Cervical Muscle Fat Infiltration Evaluated by Magnetic Resonance Imaging is Associated With Poor Postural Stability in Patients With Cervical Spondylotic Radiculopathy.

Study Design. A population-based, cross-sectional study. Objective. The aim of this study was to quantitatively evaluate the relationship between static postural stability and fat infiltration within cervical multifidus muscle in patients with cervical spondylotic radiculopathy (CSR). Summary of Background Data. CSR causes denervation by compression of nerve roots. This denervation is detected by fatty infiltration or results in fatty infiltration within muscles. Proprioceptive information in cervical multifidus muscle plays an important role in coordinated movement of postural stability; however, there have been few studies evaluating the relationship between postural stability and fat infiltration within cervical multifidus muscle among CSR patients. Methods. Sixteen CSR patients with C6 injuries and 25 age-matched healthy controls underwent magnetic resonance images to examine bilateral cervical multifidus muscle. For evaluation of fat within muscle, a muscle fat index (MFI) was calculated by using both measurement of cervical multifidus muscle and intermuscular fat. Participants’ postural stability at upright position with eyes-opened and eyes-closed for 60 seconds was examined by a platform. Two parameters, the total length and the area of the center of pressure (COP), were used for evaluation. Results. The CSR group showed significantly poorer postural stability than the control group (eyes-opened the total length; P < 0.05, eyes-closed the total length; P < 0.05, eyes-closed the area; P < 0.05). There were significant group differences at C4, C5, and C6 MFI (P < 0.05). In the CSR group, a correlation analysis demonstrated that the age, C4, C5, and C6 MFI values were significantly associated with the eyes-closed the total length of the COP (P < 0.05). Conclusions. Fat infiltration within muscle could lead to inhibition of normal activity of musculature. The present study suggests that fat within cervical multifidus muscle could directly cause postural instability in static standing, even though the proprioceptive information has normal lower limbs. Level of Evidence: 3

Effects of exercise on the nephron of Goto-Kakizaki rats: morphological, and advanced glycation end-products and inducible nitric oxide synthase immunohistochemical analyses

The current study aimed to examine how exercise affects morphology of the nephron, and localization of advanced glycation end-products (AGEs) and inducible nitric oxide synthase (iNOS) immunoreactivity in diabetic Goto-Kakizaki rats. Four groups of male rats were studied. WIS SED (Wistar rats; sedentary) group served as a control. Other groups were WIS EX (Wistar rats; exercise), GK SED (Goto-Kakizaki diabetic rats; sedentary) and GK EX (Goto-Kakizaki diabetic rats; exercise) groups. The rats in EX groups were subjected to 15weeks of treadmill running at a speed of 15m/min for a total of 30minutes, three times a week. Changes in the structure of renal corpuscles and in the distribution of AGEs- and iNOS-immunoreactive cells of the uriniferous tubules were evaluated. Every parameter of GK EX was significantly different from that of GK SED (area of Bowmans capsules: p<0.001, area of glomeruli: p<0.05 and the occupancy of a glomerulus: p<0.05). These findings suggest that exercise may ameliorate glomerular filtration rate (GFR). The localizations of AGEs and iNOS immunostaining in the uriniferous tubules were similar in each group. Immunohistochemical assays revealed that the number of the AGEs and iNOS immunopositive cells of the proximal tubule of cortico-deep layer in EX groups were markedly greater than those in SED groups and that iNOS expression in GK EX was significantly higher than GK SED (p<0.05). Exercise seems to normalize the GFR and glomerular filtrate absorption from the uriniferous tubules in Goto-Kakizaki diabetic rats with the recovered shape of renal corpuscles and may be involved in the absorption and catabolization of AGEs with iNOS-related reactions for reabsorption.

Effects of vestibular rehabilitation on gait performance in poststroke patients: a pilot randomized controlled trial

The effects of vestibular rehabilitation on poststroke patients are unknown. This study aimed to investigate whether or not vestibular rehabilitation would improve both the vestibulo–ocular reflex and gait performance of patients with poststroke hemiparesis. Twenty-eight patients with stroke were assigned randomly to either an experimental group (N=14) or a control group (N=14). The experimental group performed the conventional physical therapy for 40 min and vestibular rehabilitation for 20 min, as a 60 min session, during the first 3 weeks and then completed only the conventional intervention for 60 min for the following 3 weeks. The control group performed only the 60 min conventional physical therapy for 6 weeks. Both groups were measured using the gaze stabilization test, the 10 m walking test, the timed up and go test, and the dynamic gait index. Patients were assessed at baseline, and at 3 and 6 weeks. Although the control group showed no significant difference in any outcome measures, the experimental group showed an improvement in gaze stabilization test scoring, which increased significantly after 3 weeks compared with the baseline (P=0.030). The dynamic gait index was also significantly increased after 3 and 6 weeks compared with the baseline (P=0.049 and 0.024, respectively). This study indicated that vestibular rehabilitation might improve poststroke patients’ vestibulo–ocular reflex. Moreover, patients might show improved gait performance at least up to 3 weeks after the vestibular intervention by the sensory reweight to coordinate vestibular input.

Neuropsychology in Japan: history, current challenges, and future prospects

Abstract Objective: The purpose of this special issue was to describe the cross-cultural differences in neuropsychology throughout the world. The current state of neuropsychology in Japan is discussed in this manuscript. Method: Information on six topics, including (1) the history of Japanese neuropsychology, (2) licensure system, (3) job opportunities, (4) neuropsychological clinical services, (5) neuropsychological tests, and (6) neuropsychological research, was gathered via literature searches, official organization websites, and personal communication with clinical psychologists and other professionals in Japan. Results: Neuropsychology reached Japan from the west in the late 1800s, a period of rapid political and social modernization. Professional associations were founded in the 1960s and 1970s and continued to grow. The need for neuropsychological assessment in Japan is growing; however, credential requirements for neuropsychologists have not yet been established. To practice clinical psychology in Japan, one must obtain a Master’s degree and pass a licensure examination that is administered by a private professional foundation. Clinical psychologists often conduct neuropsychological tests; however, they have little training in neuropsychological assessment. While many western neuropsychological tests have been translated into Japanese and are used in clinical settings, the majority of translated tests have not been standardized and their psychometric properties remain poorly understood. Standardization and development of normative data in Japan is warranted. Conclusions: Given that needs for neuropsychological services are increasing, it is essential for clinical psychologists in Japan to improve their skills in neuropsychological evaluations. Japanese graduate schools must work to establish neuropsychology programs to educate and train clinical neuropsychologists.

Effect of neck and trunk rotation speeds on cerebral cortex activity and standing postural stability: a functional near-infrared spectroscopy study.

[Purpose] The aim of the present study was to determine whether different neck and trunk rotation speeds influence standing postural stability or frontal and temporal cortical activity during rotation in healthy young adults. [Subjects and Methods] Twelve healthy volunteers participated in this study. A custom turn-table operated by one of the experimenters was placed on a platform to assess postural perturbation. Subjects were asked to stand barefoot on the turn-table in an upright position with their feet together, and measurements were obtained during high- and low-speed rotations. Postural stability was tested using a force platform and a head sensor. Cerebral cortex activity was measured using functional near-infrared spectroscopy. Brain activity, center of pressure, and head perturbation were measured simultaneously for each subject. [Results] Significant differences were found in the center of pressure and the head angular velocity between high- and low-speed rotations. However, compared to baseline, oxygenated hemoglobin levels were not significantly different during high- or low-speed rotations. [Conclusion] Automatic postural responses to neck and trunk rotation while standing did not significantly activate the cerebral cortex. Therefore, the response to stimuli from the feet may be controlled by the spinal reflex rather than the cerebral cortex.

Poor gait performance is influenced with decreased vestibulo-ocular reflex in poststroke patients

The vestibulo-ocular reflex (VOR) exerts a significant influence on gait performance. Therefore, a decrease in VOR function could worsen gait impairments in patients with poststroke hemiparesis. The effects of decreased VOR function on gait performance could be further exacerbated by aging-related physical weakness and impaired motor function of the hemiparetic lower limb. The aim of our study was to evaluate the possible synergistic effect of aging and impairment in lower extremity function and the VOR on walking ability of poststroke hemiplegic patients. The VOR was evaluated, using the gaze-stabilization test (GST), in 75 patients with a poststroke hemiplegia. Lower extremity function was assessed using the Fugl-Meyer assessment (FMA-LE). Gait performance was evaluated using the 10-m walking test, the timed up-and-go, and the dynamic gait index (DGI). The relationships between gait performance and age, FMA-LE and GST, as well as whether age, FMA-LE, and/or GST were significant predictors of gait performance were evaluated. The 10-m walking test, timed up-and-go and DGI were significantly correlated to the FMA-LE and GST (P<0.05). On stepwise multiple regression analysis, the GST remained a significant predictor of the DGI (P<0.001). The present study indicates that decreased VOR function after stroke contributes to impairments in gait both in simple and in dual-task walking tests.