[Show abstract][Hide abstract] ABSTRACT: Purpose:
Sensorimotor rhythm patterns in patients with lower limb amputations might be altered because of reorganization of the sensorimotor cortices. The authors evaluated the sensorimotor rhythm of motor imagery (MI) in healthy subjects and patients with lower limb amputations. In addition, the authors investigated whether transcranial direct current stimulation (tDCS) could modulate sensorimotor rhythm control.
Six healthy subjects and six patients with lower limb amputations were assigned to receive anodal, cathodal, or sham tDCS over the foot motor area in a randomized order. The authors evaluated event-related desynchronization and event-related synchronization (ERS) of unilateral hand and bilateral foot MI before and after tDCS.
Beta ERS of foot MI in patients with lower limb amputations was significantly lesser than that in healthy subjects. Compared with sham stimulation, cathodal tDCS enhanced beta ERS of foot MI in patients with lower limb amputations. In contrast, anodal tDCS decreased beta ERS of foot MI in healthy subjects.
This is the first study to demonstrate that cathodal tDCS can enhance a weak beta ERS of foot MI in patients with lower limb amputations. These findings might contribute in improving the effectiveness of sensorimotor rhythm-based brain computer interface for gait restoration after lower limb amputation.
Journal of clinical neurophysiology: official publication of the American Electroencephalographic Society 08/2014; 32(1). DOI:10.1097/WNP.0000000000000123 · 1.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Although diffuse axonal injury (DAI) frequently manifests as cognitive and/or motor disorders, abnormal brain findings are generally undetected by conventional imaging techniques. Here we report the case of a patient with DAI and hemiparesis. Although conventional MRI revealed no abnormalities, diffusion tensor imaging (DTI) and fibre tractography (FT) revealed the lesion speculated to be responsible for hemiparesis. A 37-year-old woman fell down the stairs, sustaining a traumatic injury to the head. Subsequently, she presented with mild cognitive disorders and left hemiparesis. DTI fractional anisotropy revealed changes in the right cerebral peduncle, the right posterior limb of the internal capsule, and the right corona radiata when compared with the corresponding structures observed on the patient's left side and in healthy controls. On FT evaluation, the right corticospinal tract (CST) was poorly visualised as compared with the left CST as well as the CST in healthy controls. These findings were considered as evidence that the patient's left hemiparesis stemmed from DAI-induced axonal damage in the right CST. Thus, DTI and FT represent useful techniques for the evaluation of patients with DAI and motor disorders.
Case Reports in Medicine 11/2013; 2013:321496. DOI:10.1155/2013/321496
[Show abstract][Hide abstract] ABSTRACT: We assessed whether subitem scores on the Mini-Mental State Examination (MMSE) associated independently with cerebral white matter hyperintensity (WMH) and lacunar infarction (LI). Magnetic resonance imaging (MRI) and neuropsychological evaluation (MMSE) were performed in 1008 elderly individuals from the Ohasama Study (348 men, 660 women [65.5%]; age 68.0 ± 6.0 [mean ± SD] years; MMSE score, 26.5 ± 2.9). The relationships between MRI findings and MMSE subitem scores were analyzed by logistic regression. Significant associations were observed between the MMSE subitems "Orientation to place" and WMH, and "Copy a figure" and LI. Pathological changes were detected by brain MRI associated with a decrease in cognitive function in healthy elderly individuals.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to determine if side of cerebral hemisphere lesion affects the prevalence and time course of pushing behavior (PB) after stroke.
A total of 1660 patients with acute stroke were investigated. PB was assessed using the standardized Scale for Contraversive Pushing. Risk ratios were used to evaluate the differences in the prevalence of PB between right cerebral hemisphere-damaged (RCD) and left cerebral hemisphere-damaged (LCD) patients. The differences in the time course among 35 (27 RCD and 8 LCD) patients were evaluated by analyzing Scale for Contraversive Pushing scores with the Kaplan-Meier method using a log-rank test.
PB was observed in 156 (9.4%) patients. The prevalence of PB was significantly higher in RCD (97 of 556 [17.4%]) than in LCD (57 of 599 [9.5%]) patients; risk ratio was 1.83 (95% CI, 1.35-2.49). The log-rank test indicated that RCD patients exhibited a significantly slower recovery than LCD patients (P=0.027).
The number of RCD patients who exhibited PB was higher than that of LCD patients. The duration of recovery from PB was longer in RCD patients than in LCD patients.
[Show abstract][Hide abstract] ABSTRACT: The usefulness of ambulatory, home, and casual/clinic blood pressure measurements to predict subclinical cerebrovascular diseases (silent cerebrovascular lesions and carotid atherosclerosis) was compared in a general population. Data on ambulatory, home, and casual/clinic blood pressures and brain MRI to detect silent cerebrovascular lesions were obtained in 1007 subjects aged ≥55 years in a general population of Ohasama, Japan. Of the 1007 subjects, 583 underwent evaluation of the extent of carotid atherosclerosis. Twenty-four-hour, daytime, and nighttime ambulatory and home blood pressure levels were closely associated with the risk of silent cerebrovascular lesions and carotid atherosclerosis (all P<0.05). When home and one of the ambulatory blood pressure values were simultaneously included in the same regression model, each of the ambulatory blood pressure values remained a significant predictor of silent cerebrovascular lesions, whereas home blood pressure lost its predictive value. Of the ambulatory blood pressure values, nighttime blood pressure was the strongest predictor of silent cerebrovascular lesions. The home blood pressure value was more closely associated with the risk of carotid atherosclerosis than any of the ambulatory blood pressure values when home and one of the ambulatory blood pressure values were simultaneously included in the same regression model. The casual/clinic blood pressure value had no significant association with the risk of subclinical cerebrovascular diseases. Although the clinical indications for ambulatory blood pressure monitoring and home blood pressure measurements may overlap, the clinical significance of each method for predicting target organ damage may differ for different target organs.
[Show abstract][Hide abstract] ABSTRACT: Adrenomedullin 2/intermedin (AM2/IMD) is a novel vasodilator peptide with various effects on the renal function and cardiovascular system. An exonic insertion (I)/deletion (D) polymorphism (rs3840963) may influence generation of AM2/IMD-53, due to its location within the N-terminal sequence. We investigated the association of this polymorphism with blood pressure, renal function and the risk of silent cerebrovascular lesions in a Japanese population recruited from the Ohasama study. We recorded 24 h ambulatory blood pressure (ABP), estimated glomerular filtration rate (eGFR) and proteinuria of 1073 individuals over 40 years of age. Silent cerebrovascular lesions (lacunar infarction and white matter hyperintensity (WMH)) were recorded in 794 individuals over 55 years of age. Chronic kidney disease (CKD) was diagnosed in individuals with proteinuria and/or decreased eGFR ≤60 ml min(-1) per 1.73 m(2). DD carriers, compared with II and ID carriers, displayed significantly higher 24 h ABP (127.4 vs. 122.0 and 122.9 mm Hg, respectively, in systolic ABP, P=0.009; and 74.8 vs. 71.3 and 72.5 mm Hg, respectively, in diastolic ABP, P=0.002), and lower eGFR (75.4 vs. 82.6 and 82.9 ml min(-1) per 1.73 m(2), respectively, P=0.04). DD carriers also had a significantly higher odds ratio (OR) for prevalence of CKD (OR: 2.7, P=0.003), presence of lacunar infarction (OR: 2.4, P=0.01) and WMH (OR: 2.7, P=0.003), compared with II carriers. The AM2/IMD I/D polymorphism is associated with renal dysfunction, blood pressure regulation and asymptomatic cerebrovascular diseases in the Japanese general population.
Hypertension Research 08/2011; 34(12):1327-32. DOI:10.1038/hr.2011.131 · 2.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Arterial stiffness is a risk factor for symptomatic stroke, and is associated with symptomatic cerebral infarction and cognitive impairment. Hence, we hypothesized that arterial stiffness would be a significant determinant of silent cerebrovascular lesions.
The subjects were 363 individuals without symptomatic cerebrovascular lesions who had their arterial stiffness assessed by brachial-ankle pulse wave velocity (baPWV) measurement. The subjects were classified into two groups by the presence or absence of lacunar infarcts, as well as into three groups by grade of white matter hyperintensity (WMH). baPWV was compared among these groups.
Eighty-six subjects had lacunar infarcts. Of 138 subjects with WMHs, 102 were classified as having grade 1 and 36 as having grade 2 or 3 WMHs. baPWV was significantly higher in subjects with lacunar infarcts than in those without (17.3 ± 0.3 vs. 16.4 ± 0.2 m/s). baPWV tended to increase with higher WMH grade (16.2 ± 0.2, 16.9 ± 0.3, and 17.8 ± 0.5 m/s in grade 0, 1, and 2 or 3, respectively) after adjustments for confounding factors. The adjusted odds ratio (OR) for lacunar infarcts in subjects with middle-tertile baPWV was significantly higher (OR, 2.37; 95% confidence interval, CI, 1.10-5.11) and the OR in subjects with the highest-tertile baPWV tended to be higher (OR 2.26; 95% CI 0.99-5.45) compared with the lowest-tertile baPWV. The adjusted OR for WMH tended to increase with increased baPWV.
Arterial stiffness appeared to be associated with the presence of a lacunar infarct and WMH, independently of the risks for other cerebrovascular diseases.
[Show abstract][Hide abstract] ABSTRACT: Recent studies have revealed that (pro)renin receptor ((P)RR), a newly identified member of the renin-angiotensin system, is associated with organ damage that occurs with cardiovascular disease. We investigated the association of genetic polymorphisms in the (P)RR gene with lacunar infarction, white matter hyperintensity and left ventricular hypertrophy (LVH) in a Japanese general population recruited from the Ohasama study, a Japanese cohort study. A total of 779 subjects (men=250 and women=529) were recruited. For the association study, we selected three polymorphisms: -782A>G (rs2968915), intervening sequence (IVS)5+169C>T (rs5918007) and +1513A>G (rs6609080). In women, the prevalence of lacunar infarction and LVH was significantly higher in subjects with the +1513GG genotype than in those with the AA or AG genotypes (lacunar infarction: P=0.01, LVH: P=0.003). Plasma renin activity (PRA) levels in women with the GG genotype were significantly lower than in women with the AA or AG genotypes (P=0.01). Multiple logistic regression analysis adjusted for confounding factors demonstrated that +1513A>G polymorphism was significantly and independently associated with the risk of lacunar infarction (trend P=0.03) and LVH (trend P=0.003). In men, there were no significant differences in lacunar infarction, LVH or PRA levels among the three genotypes. The polymorphism of the (P)RR gene +1513A>G is associated with lacunar infarction and LVH in Japanese women. These results suggest that (P)RR has a role in organ damage in humans.
Hypertension Research 01/2011; 34(4):530-5. DOI:10.1038/hr.2010.274 · 2.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: No previous study has investigated the association of kidney dysfunction with silent lacunar infarcts and white-matter hyperintensity (WMH) independent of ambulatory blood pressure (BP).
A cross-sectional study involving 1,008 participants (mean age 66 years) from a general population of Ohasama, Japan, was conducted. Calculated creatinine clearance (CCr) was estimated using the Cockcroft-Gault equation. In continuous and categorical analyses, the association between CCr and the prevalence of silent lacunar infarcts and WMH was investigated. Silent lacunar infarcts and WMH were detected on MRI. Multiple logistic regression analysis adjusted for 24-hour ambulatory BP, sex, age, body mass index, smoking and drinking status, antihypertensive medication, and histories of hypercholesterolemia, diabetes mellitus and heart disease was performed.
On univariate analysis, decreased CCr (continuous variable) and CCr <60 ml/min/1.73 m(2) (categorical variable) were significantly associated with lacunar infarcts and WMH. After adjustment, each 1-standard-deviation decrease in CCr (odds ratio = 1.22; p = 0.036) and CCr <60 ml/min/1.73 m(2) (odds ratio = 1.68; p = 0.007) was significantly associated with a high prevalence of lacunar infarcts. Even when 24-hour ambulatory BP was within the normal range (<130/80 mm Hg), CCr <60 ml/min/1.73 m(2) was associated with a high prevalence of lacunar infarcts (odds ratio = 1.62; p = 0.047). CCr <60 ml/min/1.73 m(2) and 24-hour ambulatory BP had additive effects on lacunar infarcts. After the same adjustment, the association between CCr and WMH was not significant.
CCr is closely associated with lacunar infarcts, suggesting that kidney dysfunction in the elderly is an independent risk factor or predictor for silent lacunar infarcts.
[Show abstract][Hide abstract] ABSTRACT: It has been shown that mild to moderate exercise can accelerate gastric emptying in humans. However, understanding of the underlying mechanism is hampered by the lack of appropriate animal models. To investigate the effects of mild exercise on gastric motility, we developed an animal model, in which strain gauge transducers were surgically planted on the antral surfaces of female Sprague-Dawley rats. We continuously recorded the contractions of gastric circular muscle in unrestrained conscious rats, divided into four groups: sham-operated exercise, sham-operated sedentary, vagotomized exercise, and vagotomized sedentary. The rats were trained for 3 weeks, and gastric motility was monitored before and after exercise. Although exercise accelerates gastric antral contraction in sham-operated rats, this effect was absent in the vagotomized exercise group, indicating the involvement of the vagal nerve in the exercise-mediated increase in gastric motility. Among the four groups, daily food intake was highest in the sham-operated exercise group. In contrast, the vagotomized exercise group exhibited the smallest body weight gain. Severe gastric retention was observed in vagotomized rats, suggesting a role of the vagal nerve in facilitating food movement and digestion in the stomach. Moreover, at the end of the 3-week exercise, there were no differences in plasma levels of growth hormone, peptid YY, and ghrelin among the four groups. These results indicate that in response to a mild physical exercise challenge, the vagal nerve stimulates gastric motility and enhances the ability of the stomach to process food. Our findings highlight the significance of neuronal control of stomach function.
The Tohoku Journal of Experimental Medicine 01/2010; 222(2):155-63. DOI:10.1620/tjem.222.155 · 1.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Although diffuse axonal injury (DAI) usually ellicits cognitive disorders, abnormal brain findings are generally undetected by conventional imaging techniques. The aim of this study was to evaluate the feasibility of using diffusion tensor imaging (DTI) to detect lesions in DAI patients and to investigate the correlation between DAI lesions and cognitive disorders. We examined 16 healthy controls and 11 patients with DAI. Using voxel-based analysis, we found that there were significantly more brain regions with decreased fractional anisotropy (FA) in the brain but DAI patients compared to healthy controls (p < 0.001), whereas few lesions were detected via conventional magnetic resonance imaging. There was a significant relationship between the results of the Wechsler Adult Intelligence Scale-Revised, Trail Making Test, and some indices of the Wechsler Memory Scale-Revised and the decreased FA observed in various areas of the brain (p < 0.001). The total cognitive scores on the functional independence and functional assessment measures, which represent behavioral problems, were correlated with the cluster (number of DAI lesions, p = 0.007) and voxel numbers (total size of all DAI lesions, p = 0.001). In the fiber tractography-based analysis, DAI patients with memory disorders showed an interruption of fibers within the fornix compared to healthy controls. These results indicate that DTI is a useful technique not only for detecting DAI lesions but also for examining cognitive disorders in DAI patients.
Journal of neurotrauma 07/2009; 26(11):1879-90. DOI:10.1089/neu.2008-0839 · 3.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective To investigate the risk of silent cerebrovascular lesions in individuals with masked hypertension (MHT) and white-coat hypertension. Methods Self-measured home blood pressure (HBP) and casual blood pressure (CBP) measurements were recorded in 1060 individuals at least 55 years of age (mean age, 66.3 years) in a general population of Ohasama, Japan. The relationships between silent cerebrovascular lesions (white matter hyperintensity and lacunar infarct) detected on MRI and four blood pressure groups [sustained normal blood pressure (SNBP), HBP <135/85 mmHg, CBP <140/ 90 mmHg; white-coat hypertension, HBP <135/85 mmHg, CBP > or =140/90 mmHg; MHT, HBP > or =135/85 mmHg, CBP <140/90 mmHg; sustained hypertension, HBP > or =135/85 mmHg, CBP > or =140/90 mmHg] were examined using multivariate analysis adjusted for possible confounding factors. Results The odds ratios of sustained hypertension (1.74, 95% confidence interval 1.18-2.57) and MHT (2.31, 95% confidence interval 1.32-4.04) for the presence of silent cerebrovascular lesions were significantly higher than the odds ratio of SNBP, whereas there was no significant difference between white-coat hypertension and SNBP (1.03, 95% confidence interval 0.75-1.41). The odds ratios for the presence of either lacunar infarct or white matter hyperintensity in the four groups were similar to those for silent cerebrovascular lesions. Conclusion The present study is the first to demonstrate that the risk of silent cerebrovascular lesions is higher with MHT than with SNBP and similar to that of sustained hypertension.
Journal of Hypertension 05/2009; 27(5):1049-55. DOI:10.1097/HJH.0b013e3283298522 · 4.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The Manual Function test (MFT) is an upper-limb function assessment measure for hemiparetic patients after stroke. This study represents the reliability and validity of the MFT.
Ninety patients within half a year after stroke onset were hospitalized from August 2005 through November 2006. Test-retest reliability, interrater reliability, and internal consistency reliability of MFT were investigated. Validity of the MFT was evaluated with the Brunnstrom Stage, the Stroke Impairment Assessment Set, and the Barthel Index.
The test-retest reliability coefficient and interrater reliability of the MFT were consistently above 0.95. Cronbach's alpha coefficient as internal consistency of eight items was also 0.95. With respect to the validity of the MFT, it had a correlation of >0.8 with both the Brunnstrom Stage and the Stroke Impairment Assessment Set. The correlation among task items within each category was also high. There was a higher correlation (rho = 0.647) between the MFT and Barthel Index. Among the Barthel Index items, "dressing" had the highest correlation with the MFT, which indicates that upper-limb functions and degree of independence in dressing are highly correlated.
It was concluded that the MFT offers reliable and valid methods for assessing for upper-limb functional disorders.
American journal of physical medicine & rehabilitation / Association of Academic Physiatrists 12/2008; 88(3):247-55. DOI:10.1097/PHM.0b013e3181951133 · 2.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Stroke is the leading cause of long-term disability. Accurate assessment of motor function is important for documenting disability and the effectiveness of rehabilitative treatment. The Manual Function Test (MFT) was developed to evaluate unilateral manual performance in hemiparetic patients after stroke. This test consists of eight items, including the pegboard task, an item assessing dexterity. The total MFT score can range from 0 (severely impaired) to 32 (full function). We sought to determine normative data and explore influences of age, gender, and hand dominance. Three-hundred thirty-three healthy adult subjects between 20 and 90 years old were studied. Total MFT scores showed negative relationship to age. Compared with subjects in their 20s, those 50 or more years old had lower total MFT scores for dominant hands, as did those 40 or more years old for nondominant hands. For subjects in their 30s and 50s, total MFT scores for women were greater than for men concerning nondominant hands. No such gender difference in total MFT scores was noted for dominant hands. In the pegboard test, the number of pegs achieved for dominant hands was related to age when age was 50 or over, and when age 40 or over for nondominant hands. However, rates of decline in numbers of pegs achieved were similar between hands. In determining MFT norms, total score and items testing dexterity were influenced by age, gender, and hand dominance.
The Tohoku Journal of Experimental Medicine 04/2008; 214(3):257-67. DOI:10.1620/tjem.214.257 · 1.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the effects of transcranial magnetic stimulation synchronized with maximal effort to make a target movement in patients with chronic hemiplegia involving the hand.
Non-randomized double-blinded controlled trial.
Nine chronic patients with hemiplegia who were unable to fully extend the affected fingers following stroke.
Patients were assigned to receive 100 pulses of active or sham transcranial magnetic stimulation of the affected hemisphere per session. Each active or sham pulse was delivered during maximal effort at thumb and finger extension as a target movement. A blinded rater assessed stroke impairments at baseline, immediately after, and one week after 4 weekly transcranial magnetic stimulation sessions. Motor evoked potential amplitudes were measured at each session.
All sessions were completed without adverse effects. Immediately after the fourth transcranial magnetic stimulation session, 4 of 5 patients in the active transcranial magnetic stimulation group (80%) had either reduced wrist flexor spasticity or improved manual performance; no such change occurred in the sham group (Fisher's exact test, p < 0.05). Effects persisted one week later. In the active transcranial magnetic stimulation group, 3 patients who showed an increase in motor evoked potential amplitudes all had improvement in clinical assessments.
Transcranial magnetic stimulation synchronized with maximum effort to make a target movement improved hand motor function in patients with chronic hemiplegia.
Journal of Rehabilitation Medicine 01/2008; 40(1):49-54. DOI:10.2340/16501977-0133 · 1.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Delayed-onset involuntary movements have been described after thalamic stroke.
We treated a patient with involuntary movements that increased after ventriculoperitoneal shunting (VPS) for normal pressure hydrocephalus (NPH) following thalamic haemorrage. One and one-half years after right thalamic and intraventricular haemorrhage, NPH suggested clinical evaluation and neuroimaging studies in a 56-year-old man.
Hemidystonia and pseudochoreoathetosis were evident in the left arm, leg and trunk. Proprioceptive impairment and mild cerebellar dysfunction affected the left upper and lower extremity. Yet the patient could walk unassisted and carry out activities of daily living (ADL) rated as 90 points according to the Barthel Index (BI). Lumbar puncture lessened both gait disturbance and cognitive impairment. After VPS, cognition and urinary continence improved, but involuntary movements worsened, precluding unaided ambulation and decreasing the BI score to 65 points. Computed tomography after VPS showed resolution of NPH, while single-photon emission computed tomography showed increased cerebral blood flow after VPS.
Increased cerebral blood flow after VPS is suspected to have promoted development of abnormal neuronal circuitry.