Michinari Fukuda

Neuronal hyperexcitability in stroke-like episodes of MELAS syndrome

Background The pathogenesis of stroke-like episodes in patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) remains unknown. Methods Fourteen stroke-like episodes in six patients with MELAS were studied using clinical, neuroradiologic, and electrophysiologic approaches. In two patients postmortem examination was done. Results Headache and epileptic seizure were the most common presenting symptoms. In 13 of 14 episodes the cerebral cortex was primarily involved with variable subcortical edema particularly in the temporal, occipital, and parietal cortex. Repeated MRI performed in two episodes revealed progressive spread of the cortical lesion to the surrounding cortex for a few weeks after the onset of symptoms. In 6 of 11 episodes T1-weighted hyperintense cortical signal compatible with cortical laminar necrosis was seen during subacute stage of the episode. Fat-suppression MRI confirmed intracortical gyral hemorrhage in one episode. Petechial gyral microhemorrhages were also pathologically confirmed in the autopsy of another patient. In 9 of 11 episodes focal epileptiform discharges on EEG were noted in the acute brain lesion. In seven of nine episodes focal cortical hyperperfusion was seen in SPECT studies. Conclusion The stroke-like episodes in MELAS may reflect neuronal hyperexcitability, which increases energy demand and creates energy imbalance between energy requirement and adequate availability of adenosine triphosphate due to oxidative phosphorylation defect particularly in the susceptible neuronal population, causing cortical necrosis. The episodic nature of stroke-like episodes is unexplained.

Syntactic comprehension in patients with amyotrophic lateral sclerosis.

Recent neuropsychological studies of patients with amyotrophic lateral sclerosis (ALS) have demonstrated that some patients have aphasic symptoms, including impaired syntactic comprehension. However, it is not known if syntactic comprehension disorder is related to executive and visuospatial dysfunction. In this study, we evaluated syntactic comprehension using the Syntax Test for Aphasia (STA) auditory comprehension task, frontal executive function using the Frontal Assessment Battery (FAB), visuospatial function using Ravens Coloured Progressive Matrices (RCPM), and dementia using the Hasegawa Dementia Scale-Revised (HDS-R) in 25 patients with ALS. Of the 25 patients, 18 (72%) had syntactic comprehension disorder (STA score < IV), nine (36%) had frontal executive dysfunction (FAB score < 14), six (24%) had visuospatial dysfunction (RCPM score < 24), and none had dementia (HDS-R score < 20). Nine of the 18 patients with syntactic comprehension disorder (50%) passed the FAB and RCPM. Although sample size was small, these patients had a low STA score but normal FAB and RCPM score. All patients with bulbar onset ALS had syntactic comprehension disorder. These results indicate that it might be necessary to assess syntactic comprehension in patients with bulbar onset ALS. The implications of these findings are discussed in relation to the pathological continuum of ALS.

Sniff Nasal Inspiratory Pressure in Healthy Japanese Subjects: Mean Values and Lower Limits of Normal

Background: When assessing respiratory muscle strength using sniff nasal inspiratory pressure (SNIP), it is important to consider ethnic differences. Therefore, it is necessary to determine the mean values and lower limits of normal for SNIP in the Japanese population. Objective: To determine the mean values and lower limits of normal for SNIP, which is used as an assessment of inspiratory muscle strength, in healthy Japanese subjects. Methods: A total of 223 healthy Japanese volunteers (112 men, 111 women), aged 18–69 years, were studied; none had a history of pulmonary disease, heart disease, neuromuscular disease or sinusitis. To measure SNIP, a nasal plug was inserted into one nostril and the mouth was kept closed. Each subject was asked to take short, sharp sniffs with maximal effort from functional residual volume. Results: Based on the intraclass correlation coefficient, SNIP measurements showed good reproducibility in both men and women. The mean SNIP values were 76.8 ± 28.9 cm H2O in men and 60.0 ± 20.0 cm H2O in women; the values were significantly higher in men than in women (p < 0.01). On stepwise multiple linear regression analysis, the SNIP values were negatively related to age in men and positively related to body mass index (BMI) in women. The lower limits of normal for SNIP were 32.9 cm H2O in men and 28.8 cm H2O in women. Conclusions: In healthy Japanese subjects, the mean SNIP value was higher in men than in women. In Japanese subjects, SNIP values appear to be related to age in men and BMI in women.

Motor Cortex-Evoked Activity in Reciprocal Muscles Is Modulated by Reward Probability

Horizontal intracortical projections for agonist and antagonist muscles exist in the primary motor cortex (M1), and reward may induce a reinforcement of transmission efficiency of intracortical circuits. We investigated reward-induced change in M1 excitability for agonist and antagonist muscles. Participants were 8 healthy volunteers. Probabilistic reward tasks comprised 3 conditions of 30 trials each: 30 trials contained 10% reward, 30 trials contained 50% reward, and 30 trials contained 90% reward. Each trial began with a cue (red fixation cross), followed by blue circle for 1 s. The subjects were instructed to perform wrist flexion and press a button with the dorsal aspect of middle finger phalanx as quickly as possible in response to disappearance of the blue circle without looking at their hand or the button. Two seconds after the button press, reward/non-reward stimulus was randomly presented for 2-s duration. The reward stimulus was a picture of Japanese 10-yen coin, and each subject received monetary reward at the end of experiment. Subjects were not informed of the reward probabilities. We delivered transcranial magnetic stimulation of the left M1 at the midpoint between center of gravities of agonist flexor carpi radialis (FCR) and antagonist extensor carpi radialis (ECR) muscles at 2 s after the red fixation cross and 1 s after the reward/non-reward stimuli. Relative motor evoked potential (MEP) amplitudes at 2 s after the red fixation cross were significantly higher for 10% reward probability than for 90% reward probability, whereas relative MEP amplitudes at 1 s after reward/non-reward stimuli were significantly higher for 90% reward probability than for 10% and 50% reward probabilities. These results implied that reward could affect the horizontal intracortical projections in M1 for agonist and antagonist muscles, and M1 excitability including the reward-related circuit before and after reward stimulus could be differently altered by reward probability.

Repeatability of Brain Volume Measurements Made with the Atlas-based Method from T1-weighted Images Acquired Using a 0.4 Tesla Low Field MR Scanner.

Purpose: An understanding of the repeatability of measured results is important for both the atlas-based and voxel-based morphometry (VBM) methods of magnetic resonance (MR) brain volumetry. However, many recent studies that have investigated the repeatability of brain volume measurements have been performed using static magnetic fields of 1–4 tesla, and no study has used a low-strength static magnetic field. The aim of this study was to investigate the repeatability of measured volumes using the atlas-based method and a low-strength static magnetic field (0.4 tesla). Materials and Methods: Ten healthy volunteers participated in this study. Using a 0.4 tesla magnetic resonance imaging (MRI) scanner and a quadrature head coil, three-dimensional T1-weighted images (3D-T1WIs) were obtained from each subject, twice on the same day. VBM8 software was used to construct segmented normalized images [gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) images]. The regions-of-interest (ROIs) of GM, WM, CSF, hippocampus (HC), orbital gyrus (OG), and cerebellum posterior lobe (CPL) were generated using WFU PickAtlas. The percentage change was defined as [100 × (measured volume with first segmented image−mean volume in each subject)/(mean volume in each subject)] The average percentage change was calculated as the percentage change in the 6 ROIs of the 10 subjects. Results: The mean of the average percentage changes for each ROI was as follows: GM, 0.556%; WM, 0.324%; CSF, 0.573%; HC, 0.645%; OG, 1.74%; and CPL, 0.471%. The average percentage change was higher for the orbital gyrus than for the other ROIs. Conclusion: We consider that repeatability of the atlas-based method is similar between 0.4 and 1.5 tesla MR scanners. To our knowledge, this is the first report to show that the level of repeatability with a 0.4 tesla MR scanner is adequate for the estimation of brain volume change by the atlas-based method.

The relationship between bilateral knee muscle strength and gait performance after stroke: the predictive value for gait performance.

[Purpose] The purpose of this study was to assess the relationships between bilateral knee extension strengths and gait performance in subjects with poststroke hemiparesis and to predict gait performance by the paretic and nonparetic knee extension strength. [Subjects and Methods] This was a correlational study in which 238 consecutive inpatients with poststroke hemiparesis were enrolled. Knee extensor muscle strengths in paretic and nonparetic lower limbs were measured with a handheld dynamometer, and the presence or absence of impaired gait was also determined. [Results] The mean strength in the paretic lower limb was 0.90 Nm/kg, and that in the nonparetic lower limb was 1.24 Nm/kg. Discriminant analysis classified the difference between the possibility and impossibility of gait by knee extensor muscle strength (standardized discriminant coefficient: paretic, 1.32; nonparetic, 0.55). Thus, paretic and nonparetic knee extension strengths were integrated in the strength index. A threshold level of 2.0 provided the best balance between positive and negative predictive values for the strength index. [Conclusion] The results indicated that both paretic and nonparetic knee extension strengths were related to gait performance. The strength index deduced from bilateral knee extension strengths may serve as a clinically meaningful index for rehabilitation assessment and training.

Rabbit syndrome following phenol ingestion

CASE REPORT An elderly Japanese woman ingested a massive quantity of phenol in a suicide attempt. She was admitted to the Emergency Department in respiratory arrest and deep coma. Duodenogastritis was evident endoscopically. With the return of spontaneous respiration and consciousness, fine, rapid rhythmic perioral movements developed together with Parkinsonian findings. The abnormal movements were aggravated by administration of a neuroleptic and ameliorated by discontinuing the drug; they disappeared completely by hospital day 15. In addition to neuroleptic drugs, phenol intoxication may cause the rabbit syndrome by inducing cholinergic dominance with relative dopamine hypofunction in the central nervous system.

Two-year results for scoliosis secondary to Duchenne muscular dystrophy fused to lumbar 5 with segmental pedicle screw instrumentation

BackgroundInstrumentation and fusion to the sacrum/pelvis has been a mainstay in the surgical treatment of scoliosis in patients with Duchenne muscular dystrophy since the development of the intrailiac post. It is recommended for correcting pelvic obliquity. However, caudal extent of instrumentation and fusion has remained a matter of considerable debate. This study was performed to determine the efficacy and safety of stopping segmental pedicle screw constructs at L5 during surgical treatment of scoliosis associated with Duchenne muscular dystrophy (DMD).MethodsFrom May 2005 to June 2007, a total of 20 consecutive patients underwent posterior spinal fusion and segmental pedicle screw instrumentation only to L5 for scoliosis secondary to DMD. All patients had progressive scoliosis, difficulty sitting, and back pain before surgery. A minimum 2-year follow-up was required for inclusion in this study. Assessment was performed clinically and with radiological measurements. The Cobb angles of the curves and spinal pelvic obliquity were measured on the coronal plane. Thoracic kyphosis and lumbar lordosis were measured on the sagittal plane. These radiographic assessments were performed before surgery, immediately after surgery, and at a 3-month interval thereafter. The operating time, blood loss, and complications were evaluated. Patients were questioned about whether they had difficulty sitting and felt back pain before surgery and at 6 weeks, 1 year, and 2 years after surgery.ResultsA total of 20 patients, aged 11–17 years, were enrolled. The average follow-up period was 37 months. Preoperative coronal curves averaged 70° (range 51°–85°), with a postoperative mean of 15° (range 8°–25°) and a mean of 17° (range 9°–27°) at the last follow-up. Pelvic obliquity improved from 13° (range 7°–15°) preoperatively to 5° degrees (range 3°–8°) postoperatively and 6° (range 3°–9°) at the last follow-up. Good sagittal plane alignment was recreated and maintained. Only a small loss of correction of scoliosis and pelvic obliquity was noted. The mean operating time was 271 min (range 232–308 min). The mean intraoperative blood loss was 890 ml (range 660–1260 ml). The mean total blood loss was 2100 ml (range 1250–2880 ml). There was no major complication. All patients reported that difficulty sitting and back pain were alleviated after surgery.ConclusionSegmental pedicle screw instrumentation and fusion only to L5 is safe and effective in patients with DMD scoliosis of <85° and pelvic obliquity of <15°. Good sagittal plane alignment was achieved and maintained. All patients benefited from surgery in terms of improved quality of life. There was no major complication.

Quality of life in people with Parkinson's disease: the relevance of social relationships and communication.

[Purpose] Maintaining high quality of life is crucial for the rehabilitation of patients with Parkinson’s disease. The quality of life scales currently in use do not assess all quality of life domains or their importance for each individual. Therefore, a new quality of life measure, the Schedule for the Evaluation of Individual Quality of Life-Direct Weighting, was used to investigate quality of life in people with Parkinson’s disease. [Subjects and Methods] Fifteen people with idiopathic Parkinson’s disaese (average age = 80.0 years, standard deviation = 10.3 years, Hoehn & Yahr stages 1–4) were interviewed using the Schedule for the Evaluation of Individual Quality of Life-Direct Weighting. Its quality of life constructs were tested by comparing them against disease-specific quality of life (39-items Parkinson’s Disease Questionnaire), motor functioning (Unified Parkinson’s Disease Rating Scale Part III), and activities of daily living (Barthel Index). [Results] Social connections such as “family” and “friends” were revealed as important constructs of life satisfaction. The Schedule for the Evaluation of Individual Quality of Life-Direct Weighting was not significantly correlated with the 39-items Parkinson’s Disease Questionnaire, Unified Parkinson’s Disease Rating Scale Part III, or Barthel Index but was significantly correlated with the “communication” dimension of the 39-items Parkinson’s Disease Questionnaire. [Conclusion] The Schedule for the Evaluation of Individual Quality of Life-Direct Weighting detected various domains of quality of life, especially social relationships with family and friends. “Being heard” was also revealed as an essential component of life satisfaction, as it provides patients with a feeling of acceptance and assurance, possibly resulting in better quality of life.

Impact of dementia on behavioral independence and disturbance

Decreasing behavioral independence levels and increasing frequencies of behavioral disturbances are the most problematic aspects for people with dementia. However, the relative effects of dementia on these factors are unknown. We investigated variability in behavioral independence and disturbance profiles of patients with dementia.