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The activities of the suprahyoid muscles have been reported to be induced by tongue muscle contraction. The purpose of this research was to investigate whether tongue-strengthening exercises using a device cause hypertrophy of the geniohyoid muscle in healthy adults. Seven healthy young adults (3 men and 4 women, 21.0 ± 1.3 years old) received 8-week tongue muscle training with the JMS Tongue Pressure Measuring Device. The participants were instructed to press the anterior tongue against the hard palate 30 times in each session, three sessions a day, and 3 days a week. The exercise intensity was set to 60% of maximum tongue pressure in the first week, and to 80% of maximum tongue pressure for the remaining period. The training effect was evaluated by measuring (1) maximum tongue pressure value with the JMS Tongue Pressure Measuring Device, and (2) the area at rest, shortening amount, and contraction ratio of the geniohyoid muscle using ultrasonic imaging. After the 8-week training program, the maximum tongue pressure increased significantly from 44.9 to 61.6 kPa. The area of the geniohyoid muscle at rest also increased significantly from 2.3 to 2.6 cm2 after the program. There were no significant differences in the shortening amounts and the contraction ratios of the geniohyoid muscle between the values before and after the program. The tongue-strengthening exercise was useful to increase the muscle power of the geniohyoid, as well as the tongue muscles, in healthy young adults.

Objective The aim of the present study was to investigate whether anterior tongue muscle strengthening exercises can affect the strength of posterior tongue muscles. Design Eleven healthy subjects (20.6 ± 1.2 years) were included. The subjects exercised by pushing the anterior tongue to the palate 30 times, three times a day, 3 days a week for 8 weeks. The exercise intensity was set at 60% of maximum tongue pressure (MTP) in the first week and 80% of MTP for the remainder of training. After the completion of training, MTP measurements were continued every month for another 3 months to evaluate whether training effects were sustained. Results MTP was significantly increased after 8 weeks of training compared with before training. No significant differences were seen between MTP immediately after completion of training and MTP 1–3 months after completion of training. However, MTP was significantly higher 1–3 months after completion of training than before training. Conclusions The present study showed significant increases in both anterior and posterior MTPs by anterior tongue muscle strengthening exercises. In the future, a database on tongue muscle strengthening exercises in elderly persons, patients with dysphagia, etc. will need to be generated, with the aim of preventing frailty.

Transcranial magnetic stimulation (TMS) has been widely utilized to noninvasively explore the motor system during the observation of human movement. However, few studies have characterized motor cortex activity during periodic gait observation. Thus, this study examined the effects of an observer's visual experience and/or intention to imitate on corticospinal excitability during the observation of another's gait. Twenty-six healthy volunteers were included in this study and allocated to two different groups. Participants in the visual experience group had formal experience with gait observation (physical therapist training), while those in the control group did not. Motor-evoked potentials induced by TMS in the tibialis anterior and soleus muscles were measured as surrogates of corticospinal excitability. Participants were seated and, while resting, they observed a demonstrator's gait or observed it with the intention to subsequently reproduce it. Compared with the resting state, cyclic gait observation led to significant corticospinal facilitation in the tibialis anterior and soleus muscles. However, this pattern of corticospinal facilitation in the measured muscles was not coupled to the pattern of crural muscle activity during actual gait and was independent of the step cycle. This motor cortex facilitation effect during gait observation was enhanced by the observer's visual experience in a manner that was not step cycle-dependent, while the observer's intent to imitate did not affect corticospinal excitatory input to either muscle. In addition, visual experience did not modulate corticospinal excitability in gait-related crural muscles. Our findings indicate that motor cortex activity during gait observation is not in line with the timing of muscle activity during gait execution and is modulated by an individual's gait observation experience. These results suggest that visual experience acquired from repetitive gait observation may facilitate the motor system's control on bipedal walking, but may not promote the learning of muscle activity patterns.

Objective Dynamic videofluoroscopic swallow study (VFSS) is used to investigate swallowing movements. However, it requires prolonged radiation exposure and mainly provides qualitative information. Herein, we present a multi-dimensional method for analyzing swallowing based on a pulsed, low-dose fluoroscopy technique that uses serial-shot images and evaluates the size, position, and temporal profile of the bolus to obtain a more comprehensive and realistic analysis of swallowing movements. Methods Fifteen healthy adults drank two liquids: 20 mL of pure water followed by 20 mL of contrast medium mixture in a fluoroscopic study. Data were recorded in serial-shot images (7.5 frames/second, 1024 × 1024-pixel resolution, DICOM format). The images from the water and contrast swallows were inverted, synchronized, and subtracted to visualize the bolus in each frame. The pathway of the bolus was divided into 15 parts traversing the oropharynx, hypopharynx, and upper esophagus, and the total gray value was measured in each section. The results were presented as contour graphs. Results The contour graphs allowed for information on the size, anatomical location, and temporal location of the bolus during swallowing to be displayed simultaneously. Two distinct swallowing patterns were observed in the subjects. The bolus showed two peaks—one in the hypopharynx and one in the upper esophagus—in all subjects. However, in nine of the 15 subjects, the two peaks were in different frames, whereas in six of the subjects, the two peaks were in the same frame. Conclusion We developed a new method for quantitatively evaluating swallowing. The technique allows for multidimensional assessment of the size, position, and temporal profile of the movement of the bolus across the pharynx. This method evaluates the swallowing movements using sharp, high-resolution images obtained by serial-shot, pulsed fluoroscopy with low radiation exposure. Additional studies are required to further clarify the variability of swallowing patterns and their clinical relevance in the evaluation of swallowing movements in healthy subjects and in patients with swallowing disorders.

To explore the effects of qualitative or quantitative changes in walking on motor cortical excitability, a transcranial magnetic stimulation procedure was used to examine the alterations of motor-evoked potential (MEP) amplitude following walking. Eight healthy participants completed a series of two walking tasks on a treadmill at 2 km/h. The ratio of the left stance duration to the right stance duration was 1 : 2 in the asymmetrical walking task and 1 : 1 in the symmetrical walking task. In each task, walking for 10 min followed by MEP measurement for ∼4 min was repeated three times. MEP measurements were also performed before a walking task as a baseline and continued every 10 min for a further 30 min after the completion of the walking task. During slight voluntary contraction of the left tibialis anterior muscle, MEP measurements were conducted four times. Although a significant MEP depression was found after the asymmetrical walking task with increasing amount of walking, no significant decrease in MEP below baseline was observed after the symmetrical walking task throughout all measurement sessions. This MEP depression was the prominent response to the asymmetrical walking task compared with the symmetrical walking task. These findings indicate that the intentional control of walking pattern has both temporal and task-specific influences on excitability changes in the cerebral cortex, and suggest that motor cortical excitability may be altered by controlling the amount of central commands to the legs even during gait exercise.

Objective The purpose of this study was to investigate the most suitable site and method to effectively generate isometric hip flexion torque (torque value) using transcutaneous electrical or magnetic stimulation. Design Eleven healthy volunteers underwent torque value and pain degree measurements during magnetic stimulation of the iliopsoas using three coil placements. After that, the peak torque values generated under three conditions of electrical stimulation of the sartorius, the tensor fasciae latae, and the rectus femoris or that generated by magnetic stimulation of the iliopsoas were recorded at maximum tolerance intensity. Results No significant differences in torque values were observed among the three coil placements. Magnetic stimulation of the point below the inguinal ligament caused significantly more pain than the other points. Magnetic stimulation of the iliopsoas generated significantly higher torque values than did the electrical stimulation of the two hip flexor muscles together. Conclusions The hip joint was one of the most suitable regions for application of magnetic stimulation as an alternative method to electrical stimulation.

When eating solids, stage II transport (St2Tr) propels triturated food into the pharynx for bolus formation and storage before swallowing. Although the existence of St2Tr is acknowledged, the reason for its existence remains unclear. Understanding it may facilitate development of food appropriate for individuals with dysphagia. The purpose of this study was to explore how measures of duration of eating and swallowing affect the number of St2Tr cycles.Videofluorography was performed on 13 healthy subjects eating 6-g squares of banana, tofu, and cookies. Measurements included the number of St2Tr cycles, duration of processing (from food entering the mouth to onset of swallowing), pre-upper esophageal sphincter (UES) transit duration (from onset of swallowing to onset of UES transit), UES transit duration (leading edge to trailing edge passing the UES), and total sequence duration (from onset of swallowing to terminal swallow). Principal component (PC) analysis was used to identify factors affecting the number of St2Tr cycles. Analysis of covariance was performed using the 1st PC as an independent variable for predicting the number of St2Tr cycles.All four duration measures were significantly positively correlated with the number of St2Tr cycles. Analysis revealed two orthogonal PCs with variable loading. The 1st PC was a function of the timing variables. The 2nd PC was a function of the number of swallows.The number of St2Tr cycles was associated with measures of food transit duration and was greater with harder foods before processing and more viscous foods just before swallowing.

The purpose of this study was to confirm that the arytenoid regions dynamically adduct and extend upward toward the epiglottis during laryngeal elevation. While 14 healthy volunteers aged 19–32 years old swallowed 5 ml of white soft yogurt in one gulp without chewing, the movement of the arytenoid regions was observed for videoendoscopic evaluation of swallowing (VE). Each moving image was stored simultaneously on videotape. A cross-sectional area surrounded by the epiglottis and the bilateral arytenoid regions (S) and the length of a straight line passing through the anterior borders of the left and right arytenoid regions (L) were measured. The relative area of the entrance in the laryngeal vestibule was calculated as [S/L 2] before the swallowing reflex (resting condition), just before laryngeal closure, and just after laryngeal closure. [S/L 2] was smaller just before epiglottal descent than at the resting condition, and became smallest just after the epiglottis started to ascend. The mean area narrowed to 37.9% of the resting area just after laryngeal closure and in the most extreme case to 8.7% of the resting area. It was demonstrated that the arytenoid regions adducted and extended up toward the epiglottis during laryngeal elevation. The technique used to measure the cross-sectional area of the entrance in the laryngeal vestibule employing VE was an effective analytical procedure.

The rare hereditary disorder Fanconi anemia (FA) can be caused by mutations in components of the FA core complex (FancA/B/C/E/F/G/L/M), a key regulator FancD2, the breast cancer susceptibility protein BRCA2/FancD1, or the newly identified FancJ/BRIP1 helicase. By performing yeast two-hybrid (Y2H) screens using N-terminal chicken (ch) FancD2 as a bait, we have identified chFancL, the likely ubiquitin E3 ligase subunit of the FA core complex. We also found that ectopically expressed FancD2 and FancL co-immunoprecipitated in 293T cells, and this interaction was dependent on the PHD domain of FancL. FANCL-disrupted chicken DT40 cells displayed defects in both FancD2 monoubiquitination and focus formation. Importantly, cell lines lacking the FANCL or FANCD2 genes, or carrying a "knock-in" mutation of the FancD2 monoubiquitination site (where the Lys 563 residue is changed to Arg), displayed quantitatively identical defects in the repair of I-SceI-induced chromosomal breaks by homologous recombination (HR). These data establish the role of FANCL and FancD2 monoubiquitination in HR repair.

Articulation is driven by various combinations of movements of the lip, tongue, soft palate, pharynx and larynx, where the tongue plays an especially important role. In patients with cerebrovascular disorder, lingual motor function is often affected, causing dysarthria. We aimed to evaluate the effect of visual biofeedback of posterior tongue movement on articulation rehabilitation in dysarthria patients with cerebrovascular disorder. Fifteen dysarthria patients (10 men and 5 women; mean age, 70.7 ± 10.3 years) agreed to participate in this study. A device for measuring the movement of the posterior part of the tongue was used for the visual biofeedback. Subjects were instructed to produce repetitive articulation of [ka] as fast and steadily as possible between a lungful with/without visual biofeedback. For both the unaffected and affected sides, the range of ascending and descending movement of the posterior tongue with visual biofeedback was significantly larger than that without visual biofeedback. The coefficient of variation for these movements with visual biofeedback was significantly smaller than that without visual biofeedback. With visual biofeedback, the range of ascent exhibited a significant and strong correlation with that of descent for both the unaffected and affected sides. The results of this study revealed that the use of visual biofeedback leads to prompt and preferable change in the movement of the posterior part of the tongue. From the standpoint of pursuing necessary rehabilitation for patients with attention and memory disorders, visualization of tongue movement would be of marked clinical benefit.

Patients with Parkinson’s disease develop gait disturbances. Although the use of walkers is very effective for maintaining locomotive ability, patients who have symptoms such as frozen gait (FG) and festinating gait may fall even with a walker equipped with a brake as they cannot use the brake well in an emergency and fail to follow the accelerating walker. None of the studies on walking aids to date have addressed real-time detection of FG or the use of this information for the control of the walking aid, monitoring of the state of improvement in the ambulatory function, or evaluation of the effect of the use of a walker. In this study, we evaluated whether the state called FG, a characteristic symptom of Parkinson’s disease, can be detected by the use of a sensor-controlled walker with heel-to-toe pressure sensors. The following two measurements were carried out in one male healthy and a one male patient with stage 3 Parkinson’s disease by the Hoehn-Yahr scale showing mild muscle rigidity, hypokinesia, and FG. In the healthy subject, the heel-to-toe pressure showed smooth heel-to-toe shifts during the standing phase. In the patient with Parkinson’s disease, the heel-to-toe response time was about 2.4 times longer than in the healthy subject at the beginning of walking, and FG could be recorded as the difficulty in lifting the foot by the toes. Also, when FG was observed during walking, the pressure waves recorded by the same sensors showed two peaks occurring at a short interval, indicating double landings.

Background The incidence of low back pain (LBP) is high in patients with hip osteoarthritis (OA). Evidence from previous studies suggests that lumbar alignments and hip range of motion (ROM) are important etiological factors for LBP. However, no studies have investigated which factors that have the greatest influence on LBP. Objective This investigation aimed to collectively examine factors related to LBP in patients with hip OA, including lumbar lordosis angle (LLA), leg length discrepancy (LLD), and hip ROM. Methods Thirty-five patients participated in this study. LBP was treated as a dependent variable, whereas hip ROMs were treated as independent variables. Patients' age and body mass index (BMI) were recorded as confounding factors, as were LLA and LLD. A logistic regression model was performed to determine the most accurate set of variables to predict LBP. Results BMI and ROM of hip flexion on the affected side were identified as significant variables. Conclusions Our results suggest that BMI and ROM of hip flexion on the affected side are related to LBP in patients with hip OA and need to be assessed.

Our previous single-pulse transcranial magnetic stimulation (TMS) study revealed that excitability in the motor cortex can be altered by conscious control of walking relative to less conscious normal walking. However, substantial elements and underlying mechanisms for inducing walking-related cortical plasticity are still unknown. Hence, in this study we aimed to examine the characteristics of electromyographic (EMG) recordings obtained during different walking conditions, namely, symmetrical walking (SW), asymmetrical walking 1 (AW1), and asymmetrical walking 2 (AW2), with left to right stance duration ratios of 1:1, 1:2, and 2:1, respectively. Furthermore, we investigated the influence of three types of walking control on subsequent changes in the intracortical neural circuits. Prior to each type of 7-min walking task, EMG analyses of the left tibialis anterior (TA) and soleus (SOL) muscles during walking were performed following approximately 3 min of preparative walking. Paired-pulse TMS was used to measure short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) in the left TA and SOL at baseline, immediately after the 7-min walking task, and 30 min post-task. EMG activity in the TA was significantly increased during AW1 and AW2 compared to during SW, whereas a significant difference in EMG activity of the SOL was observed only between AW1 and AW2. As for intracortical excitability, there was a significant alteration in SICI in the TA between SW and AW1, but not between SW and AW2. For the same amount of walking exercise, we found that the different methods used to control walking patterns induced different excitability changes in SICI. Our research shows that activation patterns associated with controlled leg muscles can alter post-exercise excitability in intracortical circuits. Therefore, how leg muscles are activated in a clinical setting could influence the outcome of walking in patients with stroke.

The aim of this study was to investigate oropharyngeal pressure flow dynamics during dry swallowing in ten healthy subjects. Tongue pressure (TP) was measured using a sensor sheet system with five measuring points on the hard palate, and pharyngeal pressure (PP) was measured using a manometric catheter with four measuring points. The order and correlations of sequential events, such as onset, peak, and offset times of pressure production, at each pressure measuring point were analyzed on the synchronized waveforms. Onset of TP was earlier than that of PP. The peak of TP did not show significant differences with the onset of PP, and it was earlier than that of PP. There was no significant difference between the offset of TP and PP. The onset of PP was temporally time-locked to the peak of TP, and there was an especially strong correlation between the onset of PP and TP at the posterior-median part on the hard palate. The offset of PP was temporally time-locked to that of TP. These results could be interpreted as providing an explanation for the generation of oropharyngeal pressure flow to ensure efficient bolus transport and safe swallowing.

To the Editor, We are pleased to report on the development and progress of the trans-disciplinary field of Deglutology in Japan as the Japanese Society of Dysphagia Rehabilitation (JSDR) commemorates its 20th year of establishment. The JSDR includes a broad range of disciplines in order to integrate diverse knowledge and expertise and pave the way for the emerging field of Deglutition. The percentage of individuals aged over 65 years reached 25.0 % of the Japanese population in 2013 [1]. With this rapid increase in the elderly, a substantially greater demand for dysphagia rehabilitation comes up. As the progression of dysphagia diminishes both the function of swallowing and the enjoyment of eating, the objective of dysphagia rehabilitation should therefore address both the recovery of swallowing function and the restoration of pleasure while eating. Dysphagia rehabilitation is performed for a wide range of disease stages, from acute medical care to terminal support. Although a team approach is essential for effective rehabilitation, treatment can be challenging because support strategies vary considerably over time and require numerous approaches and caregivers. We normally divide the team approach in dysphagia rehabilitation into three categories according to the relationships among participating disciplines as follows: (1) the multi-disciplinary approach, where disciplines treat patients independently and have little communication with each other, (2) the inter-disciplinary approach, where related disciplines exchange information at team conferences to reach a consensus on treatment, thus promoting inter-disciplinary cooperation, and (3) the trans-disciplinary approach, where participating disciplines complement the scope of others to more efficiently integrate a team approach. The trans-disciplinary approach is particularly suitable for dysphagia rehabilitation because the size and composition of a support team may change significantly over time; complementing the scopes of associated disciplines without establishing a rigid inter-disciplinary border enables seamless care over a wider range of individuals, symptom stages, and circumstances. The JSDR was founded in 1995 under the concept of a trans-disciplinary approach for dysphagia rehabilitation. As the society now celebrates 20 years of progress and innovation, its membership has grown to more than 11,000 medical professionals (11,653 as of August 30, 2014) and involves numerous disciplines (Fig. 1) in line with the original JSDR trans-disciplinary tenets. Recently, the 20th annual conference of the JSDR held in Tokyo in September 2014 featured an international symposium that included 12 E. Saitoh Department of Rehabilitation Medicine I, School of Medicine, Fujita Health University, Toyoake, Aichi, Japan e-mail: esaitoh@fujita-hu.ac.jp

A compound nerve action potential (CNAP) recorded from surface of the skin is composed of single nerve fiber action potentials propagating at various conduction velocities (CVs). Based on this assumption, we constructed two CNAPs simulating those at the digit elicited by stimulation of the median nerve at the wrist (CNAP-Wr) and the elbow (CNAP-El). Distribution of the nerve fiber CVs used for the simulation was estimated from actual recordings of 12 healthy subjects. Mean ratio of the CNAP amplitude (CNAP-WrCNAP-El) was 2.2, and that of the duration was 0.76. First, to analyze how CV distributions affect CNAP waveforms artificially in our computer program, we altered mean CV or standard deviation (SD) of the estimated distribution, and reconstructed CNAPs. Results indicated that as the mean CV was made slower, the ratio of the CNAP amplitude increased and that of the duration decreased. Similar changes of the ratios were also shown when the SD of the CV distribution was increased without changing the mean CV. Secondly, to make constructed CNAPs more similar to actual recordings, we added artificial noise to the constructed waves and had 11 electromyographers read onset and peak latencies. The average of maximum CVs calculated from the onset latencies of CNAPs-Wr was 62m/sec, and that from the latency difference between CNAPs-Wr and -El was 70m/sec. Both CVs were slower than the genuine maximum (77m/sec) given to the simulation program. The mean CV calculated from latency difference of the major positive peaks of the CNAPs was 62m/sec being close to the mode (62m/sec) or mean (60m/sec) value of the given distribution.

The relationship between Wallerian degeneration in the brain stem and degree of motor impairment is discussed. Using MRI we studied 172 supratentorial stroke patients, whose motor impairment was graded according to Brunnstrom stage. Wallerian degeneration was represented by a T2 high-intensity area in the brain stem, and its cross-sectional extent was measured at the cerebral peduncle level. Wallerian degeneration was detected in 99 patients (57.6%). The area of T2 high intensity was significantly correlated with Brunnstrom stage. Multiple regression analysis showed that the upper extremity stage contributed most to the visualization of Wallerian degeneration. This is partly because the pyramidal tract participates in fine and precise movement. The extent of the area of Wallerian degeneration is found to be helpful in making a prognosis with respect to motor impairment in the upper extremity.

A 61-year-old woman with a history of repeated cerebral hemorrhage due to moyamoya disease was admitted to our recovery period rehabilitation ward for walking training. She suddenly noticed paresthesia in her left forearm and the palm seven days later. Brain computed tomography on that day and magnetic resonance imaging on the next day after the onset of paresthesia revealed right thalamic hemorrhage. It was suggested that the hematoma localized to a small part of the central portion of the ventroposterior lateral nucleus caused paresthesia limited to the forearm and the palm. In a recovery period rehabilitation ward, we should carefully listen to the complaints of patients who are in advanced age and have a risk like our patient. Then adequate neurological examination should be performed for the pertinent inspection diagnosis, if needed.

We report a case who developed jargonagraphia, severe aphasia and unilateral spatial neglect due to cerebral infarction in the left hemisphere. The patient was a 57 year-old left-handed woman. She suddenly developed hemiplegia on the right side and aphasia, and was admitted to our hospital. Neuropsychological examination showed non-fluent spontaneous speech. Repetition, reading and auditory comprehension were impaired. Writing was severely impaired and she showed paragraphia without meaning (jargonagraphia). Right unilateral spatial neglect and buccofacial apraxia were noted, but neither ideomotor nor ideational apraxia was observed. The mechanisms of jargonagraphia remain unknown. The localization of language function in this patient is not a mirror image of same function in dextral aphasia. Her condition was considered that free-running on motor engrams of characters stored in the right hemisphere caused jargonagraphia.

Upper extremity hemiplegia after stroke is common and disabling. Apart from conventional physical and occupational therapy, a number of additional approaches that use devices such as orthoses, prostheses, electrical stimulation, and robots have been introduced. The purpose of this review was to assess the clinical efficacy of such devices used for the affected upper extremities of acute, subacute, and chronic stroke patients. Assessments of their effectiveness and recommendations were based on the weight of published scientific evidence. The amount of evidence with respect to hand splints and shoulder slings is limited. Further study with a well-designed randomized controlled trial (RCT) is required to investigate accurately their short- and long-term efficacy. A number of studies suggested that the use of electrical stimulation for reducing shoulder subluxation or improving the function of wrist and finger extensors is effective during or shortly after the daily treatment period. The robotic approach to hemiplegic upper extremities appears to be a novel therapeutic strategy that may help improve hand and arm function. However, the longer term effectiveness after discontinuation as well as the motor recovery mechanism of electrical stimulation or robotic devices remains unclear. More research is needed to determine the evidence-based effectiveness of electrical stimulation or other devices for stroke survivors.

A computer-assisted method of estimating the distribution of muscle fiber conduction velocities is described. An electrode array composed of 2 stimulating and 4 recording electrodes is used to record surface muscle action potentials (MAPs) in response to direct muscle stimulation. The velocity distribution and the single muscle fiber action potential (SFAP) are calculated from the recorded MAPs by an iterative method of estimation. The estimation is based on the assumption that the spatial orientation of each muscle fiber viewed from the recording electrodes is the same along the muscle fibers and a MAP is recorded as a linear summation of all SFAPs. The accuracy of this estimation is demonstrated using simulated MAPs. The method is also tested on MAPs containing simulated amplifier noise, stimulus artifact, and errors in distance between electrodes. Finally we applied this method to MAP recordings of the biceps brachii in 23 healthy subjects. The velocity distribution was successfully estimated in 20 cases. The average of the estimated distributions was smaller than that described by previous workers. The reasons for the difference are discussed.

The pixel values in fat/water suppression magnetic resonance (MR) images were measured for the thigh muscles of 18 healthy volunteers to investigate age-related changes in muscle water and fat content. Prior to the human studies the reproducibility of the data was confirmed using phantoms. The standard deviations (SDs) of the pixel values for one of the phantoms examined five times were found to be within a relatively narrow range. Both the pixel values in the fat suppression images (PV1) and the pixel values in the water suppression images (PV2) of all muscles tended to be higher in the oldest group. The results indicate that the water and fat content of skeletal muscles is higher in aged persons. Moreover, the PV1 in the non-dominant limbs was found to be increased in the extensor muscles of the knee joints, while the PV2 in the non-dominant limbs did not show a significant difference, except for the rectus femoris.

T1 relaxation time (T1 time), T2 relaxation time (T2 time), and proton (rho) density in the thigh muscles of 20 normal healthy volunteers and three patients with muscle atrophy in the lower extremity were measured in order to select the useful MRI parameters for neuromuscular diagnosis. Since the standard deviation (SD) of both T1 and T2 times in each muscle was found to be within a relatively small range, these values were expected to be useful MRI parameters for neuromuscular diagnosis. On the contrary, rho density was not a valid parameter for diagnosis, as it was demonstrated to have large SDs in the muscles. The differences of these parameters in the three patients also supported the fact that MRI was useful for discriminating between the various types of muscular abnormalities based on relaxation times. The longer T1 and T2 times in women suggested that the content of water in skeletal muscle was higher in women than in men. Moreover, the T1 time in the dominant limbs was found to be shorter than in the non-dominant limbs for rectus femoris only in both men and women, while there were no differences in T2 time in these muscles.

To investigate subclinical sensory impairment in spinocerebellar degenerations, median nerve somatosensory evoked potentials (SEPs) were examined in 16 patients with chronic cerebellar ataxia who were originally diagnosed by clinical neurologists as having olivopontocerebellar atrophy (OPCA). Two types of abnormal SEP patterns were found in six patients. Two patients had the SEP pattern of peripheral neuropathy, which was also detected by peripheral sensory nerve conduction studies. Four patients had abnormal SEPs seen in patients with the lesions in the central nervous system (dorsal column, medial lemniscus). Magnetic resonance imaging (MRI) showed multiple sclerosis (MS). It is possible that clinically diagnosed OPCA sometimes includes a similar form of Friedreich's ataxia with subclinical sensory fiber neuropathy detected by SEPs and peripheral sensory conduction studies. In cases of lesions in the central nervous system demonstrated by both SEPs and MRI, there must be a follow-up in order to make a final diagnosis. In those cases, an alternative diagnosis of MS must be considered when the temporal profile of symptoms and signs characteristic of MS is observed.