Amyotrophic lateral sclerosis. Successful treatment of mucous plugging by mechanical insufflation-exsufflation

Bronchial mucous plugging is the main precipitating factor of acute respiratory failure for patients with neuromuscular disease. Manually assisted coughing and mechanical insufflation-exsufflation can effectively eliminate airway secretions without resorting to tracheal intubation provided that bulbar muscle function is sufficient to permit assisted peak cough flows of 160 l/min or greater. We now report successful use of mechanical insufflation-exsufflation to prevent acute respiratory failure for a patient with amyotrophic lateral sclerosis with no measurable peak cough flow.

Effects of Capsaicin on Older Patients with Oropharyngeal Dysphagia: A Double-Blind, Placebo-Controlled, Crossover Study

BACKGROUND/AIMS

The standard of care for older patients with oropharyngeal dysphagia (OD) is poor. Stimulation of transient receptor potential vanilloid 1 might become a pharmacological strategy for these patients. This study aimed to compare the therapeutic effect of film food containing 0.75 µg of capsaicin in these patients.

METHODS

In a crossover, randomized trial, 49 patients with OD were provided capsaicin or identical placebo at least 7 days apart. Patients' reported symptoms during repeated swallowing, the volume, pH and substance P (SP) concentrations in saliva, and cervical esophageal wall motion evaluated by ultrasonographic tissue Doppler imaging were obtained before and after capsaicin or placebo administration.

RESULTS

Significantly more patients with OD who took capsaicin experienced improvement in symptoms than those who took placebo. Salivary SP levels were significantly increased after capsaicin administration compared with placebo in the effective group. The duration of cervical esophageal wall opening was significantly shorter in capsaicin administration in the effective group. Furthermore, a significant negative correlation was found between the duration of cervical esophageal wall opening and salivary SP levels.

CONCLUSION

Elevated salivary SP concentrations stimulated by capsaicin greatly improve the safety and efficacy of swallowing, and shorten the swallow response in older patients with OD.

Dysphagia in patients with Duchenne muscular dystrophy evaluated with a questionnaire and videofluorography

PURPOSE

To investigate swallowing problems in patients with Duchenne muscular dystrophy (DMD) using a questionnaire and videofluorography (VF).

METHOD

A questionnaire survey was performed of swallowing-related symptoms and VF in 31 male patients with DMD (mean age 19.9 years, range 9 - 26 years). The relationships among age, frequency of symptoms and VF abnormalities were analysed using Spearman's rank correlation. The differences in VF abnormalities among different food textures were analysed with the Kruskal - Wallis test.

RESULTS

Symptoms related to pharyngeal phase dysfunction were more frequent than those related to oral and oesophageal phases. Coughing while eating was seen in 71% of the patients, choking while eating in 32% and the need to clear the throat in 26%. VF abnormalities were observed in 30 patients (96.8%). Common VF abnormalities included pooling in the valleculae (90.3%) and in the pyriform sinus (90.3%). Pharyngo-oral regurgitation was seen in 35.5% of the patients. Pooling in the pyriform sinus after repeated swallowing seen in VF correlated significantly with symptoms related to the pharyngeal phase (Spearman's rho 0.356 - 0.544).

CONCLUSION

Because oropharyngeal dysphagia in DMD was evident in teenage patients as well as those without clinical symptoms, VF is recommended in patients with DMD.

Practical problems and management of seating through the clinical stages of Duchenne's muscular dystrophy

OBJECTIVE

To describe seating problems in patients with Duchenne's muscular dystrophy (DMD), for the purpose of identifying management solutions that are practicable for both patient and caregiver.

DESIGN

Case series.

SETTING

A Japanese long-term care facility.

PARTICIPANTS

Ninety-five patients with DMD (mean age, 15.9+/-4.4y; Swinyard stages: stage 5, n=17; stage 6, n=24; stage 7, n=33; stage 8, n=21).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Spinal deformity types, frequency and sites of pain, wheelchair propulsive ability, activities of daily living, and caregiving-related problems.

RESULTS

Thirty-three percent of the patients belonged to the early straight group, 21% to the scoliotic group, 20% to the kyphoscoliotic group, 2% to the kyphotic group, and 24% to the extended spine group. The percentage needing support for sitting was higher in patients with spinal deformities (76% vs 0%, P<.05). Forty-one percent had pressure problems, and the percentage increased with advancing stages, with pain sites related to spinal deformity types. Self-feeding was difficult in 10 patients having spinal deformities. Four patterns of manual wheelchair propulsion were observed: upper extremity, anteroposterior trunk flexion, lateral trunk flexion, and wrist-hand patterns; and propulsion became increasingly less practical in this order. For toileting, more patients were cared for on wheelchairs with backrests reclined with stage progression. Of 60 caregivers, 58% experienced trauma related to seating systems.

CONCLUSION

The seating problems that were identified enabled specific, practical suggestions to be made for better management.

Functional status and muscle strength in people with Duchenne muscular dystrophy living in the community

OBJECTIVE

To describe activity limitation of people with Duchenne muscular dystrophy who are living in the community and to correlate it with age and muscle strength.

DESIGN

Descriptive, correlational.

SUBJECTS

Twenty-seven children with Duchenne muscular dystrophy aged 7-14 years who are living in the community.

METHODS

The subjects' activity limitation was evaluated using the Functional Independence Measure and the muscle strength of their major upper and lower limb muscles was evaluated with manual muscle testing. The Functional Independence Measure was correlated with age and manual muscle testing, and the pattern of activities of daily living limitations and factors related to it were analysed.

RESULTS

There were significant correlations between age and averaged MMT score (Spearman's rho = -0.63, p < 0.01), age and Functional Independence Measure motor score (rho = -0.52, p < 0.01), and Functional Independence Measure motor score and averaged manual muscle testing (rho = 0.77, p < 0.01). At similar manual muscle testing level, children with good cognitive function (Functional Independence Measure cognitive score > or = 26) showed significantly higher Functional Independence Measure motor scores than those with poor cognitive function (Mann-Whitney U test, p < 0.01). For individual Functional Independence Measure items, eating and bowel management were the easier, whereas transfer and stair climbing were the more difficult. Patients with mean muscle strength > or = grade 3 were rated as relatively independent, while those with a mean muscle strength < grade 3 were rated as maximal or total assistance (Mann-Whitney U test, p < 0.05).

CONCLUSION

Activities of daily living in patients with Duchenne muscular dystrophy are related to age and muscle strength, and manual muscle testing grade 3 is an important cut-off point to predict their disability.

ADL structure for nondisabled Japanese children based on the Functional Independence Measure for Children (WeeFIM)

The Functional Independence Measure for Children (WeeFIM) instrument was developed, based on the FIM instrument, to assess disability in children aged 6 mo to 7 yr. Normative data are reported for American and Japanese children, and it is increasingly used for the disabled. Our purpose was to confirm scale quality and to determine the difficulty pattern of the WeeFIM in Japan. The WeeFIM was measured in 225 children (113 girls and 112 boys) aged 6 mo to 7 yr without developmental delays. The scores were converted to an interval scale by Rasch analysis, which assumes unidimensionality of the measurement items, determines the degree of the fit to the assumption, and decides item difficulty. When the WeeFIM items were divided into two groups of motor and cognitive items to minimize misfit, the degree of misfit was acceptable, except for eating, bladder management, tub/shower transfer, and comprehension. For the motor items, grooming, bathing, and bladder control were more difficult, and stairs, bed/chair transfer, and walk or wheelchair were easier. Concerning the cognitive items, expression and comprehension were easier, and problem-solving was most difficult. When we compared item difficulty patterns in the four age groups (6-21 mo, 22-45 mo, 46-62 mo, and 63-100 mo), we found no differences, except in toilet transfer. It was more difficult for younger children, possibly because of its different pattern of chronological change, which shows rapid changes from dependent to independent levels over a short period of time. Our study confirmed the scale quality of the WeeFIM instrument with Rasch analysis and demonstrated the difficulty pattern of the WeeFIM in nondisabled Japanese children.

Virtual reality-based action observation facilitates the acquisition of body-powered prosthetic control skills

Background

Regular body-powered (BP) prosthesis training facilitates the acquisition of skills through repeated practice but requires adequate time and motivation. Therefore, auxiliary tools such as indirect training may improve the training experience and speed of skill acquisition. In this study, we examined the effects of action observation (AO) using virtual reality (VR) as an auxiliary tool. We used two modalities during AO: three-dimensional (3D) VR and two-dimensional (2D) computer tablet devices (Tablet). Each modality was tested from first- and third-person perspectives.

Methods

We studied 40 healthy right-handed participants wearing a BP prosthesis simulator on their non-dominant hands. The participants were divided into five groups based on combinations of the different modalities and perspectives: first-person perspective on VR (VR1), third-person perspective on VR (VR3), first-person perspective on a tablet (Tablet1), third-person perspective on a tablet (Tablet3), and a control group (Control). The intervention groups observed and imitated the video image of prosthesis operation for 10 min in each of two sessions. We evaluated the level of immersion during AO using the visual analogue scale. Prosthetic control skills were evaluated using the Box and Block Test (BBT) and a bowknot task (BKT).

Results

In the BBT, there were no significant differences in the amount of change in the skills between the five groups. In contrast, the relative changes in the BKT prosthetic control skills in VR1 (p < 0.001, d = 3.09) and VR3 (p < 0.001, d = 2.16) were significantly higher than those in the control group. Additionally, the immersion scores of VR1 (p < 0.05, d = 1.45) and VR3 (p < 0.05, d = 1.18) were higher than those of Tablet3. There was a significant negative correlation between the immersion scores and the relative change in the BKT scores (Spearman’s r_s = − 0.47, p < 0.01).

Conclusions

Using the BKT of bilateral manual dexterity, VR-based AO significantly improved short-term prosthetic control acquisition. Additionally, it appeared that the higher the immersion score was, the shorter the execution time of the BKT task. Our findings suggest that VR-based AO training may be effective in acquiring bilateral BP prosthetic control, which requires more 3D-based operation.

Relationship between nerve and muscle fiber conduction velocities of the same motor unit in man

To test the hypothesis that the nerve fiber conduction velocity of a motor unit is correlated with the muscle fiber conduction velocity of the unit, the collision technique was used to discriminate the motor unit action potentials elicited by stimulation of a group of nerve fibers with known conduction velocity. Muscle fiber conduction velocity was determined from the propagating action potentials of the unit recorded by a surface electrode array. A weak but significantly positive correlation was found between nerve and muscle fiber conduction velocities in the thenar muscle of human subjects. The results indicate that the size principle that governs the relation between nerve and muscle fiber size is a fairly weak principle with occasional exceptions.

Recovery of conduction velocity of muscle fiber action potential after strenuous isometric contraction

The change of conduction velocity of muscle fiber action potentials of individual motor units after loading of 50% maximal voluntary contraction was examined in biceps brachii muscles of twenty healthy male subjects. A surface electrode array, consisting of fifteen electrodes spaced at 5 mm intervals, was used to detect EMG signals during minimal isometric contraction which is adjusted so as to generate action potentials in a single motor unit. Conduction velocity was measured from the recorded signals of 14 channels. Mean conduction velocity of all subjects was 3.33 +/- 0.28 m/s (n = 20). A significant decrease of the conduction velocity was observed after contraction maintaining 50% of maximal voluntary contraction torque as long as possible. From the results of conduction velocity decrease during 6 min minimal contraction following the contraction at 50% of maximal strength, subjects were divided into two groups, having endurance times exceeding 50 s and less than 50 s, respectively. The former showed significant recovery during minimal contraction after loading, while the latter showed no apparent recovery. It was demonstrated that the conduction velocity of muscle action potentials obtained with minimal contraction decreased after strenuous contraction and the extent of its recovery was related to the endurance time of contraction which the subjects could maintain 50% of maximal strength.

Resolution of tracheostomy complications by decanulation and conversion to noninvasive management for a patient with high-level tetraplegia

OBJECTIVES

To report conversion from tracheostomy (TIV) to noninvasive intermittent positive pressure ventilation (NIV) for a continuously ventilator-dependent patient with high-level spinal cord injury (SCI) with no measurable vital capacity (VC = 0 mL) to resolve tracheostomy-associated complications.

METHODS

A case report of a 38-year-old female in a chronic care facility in Japan with a 10-year history of ventilator-dependent tetraplegia (C1 ASIA-A) presented for increasing difficulty vocalizing. She had been using a fenestrated cuffed tracheostomy tube to produce speech with the cuff deflated. Speech was increasingly hypophonic, because of tracheostoma enlargement, tube migration, and tracheal granulation.

RESULTS

The NIV was provided via nasal and oral interfaces, the ostomy was surgically closed, and vocalization resumed. Airway secretions were expulsed using manually assisted coughing. The patient returned to the community.

CONCLUSION

Conversion to NIV should be considered for ventilator-dependent patients with SCI who have adequate bulbar-innervated muscle function to permit effective speech and assisted coughing.

Diagnosis and treatments for oropharyngeal dysphagia: effects of capsaicin evaluated by newly developed ultrasonographic method

Oropharyngeal dysphagia (OD) is a common symptom in the older people, and may cause fatal complications such as aspiration pneumonia. However, there is no established treatment for OD. The relationship between the transient receptor potential vanilloid 1 (TRPV1) and substance P released by activated TRPV1 was recently demonstrated. Further, there are several reports showing that capsaicin, a specific agonist of TRPV1, can improve OD. Currently, the evaluation of swallowing is mainly performed by videofluoroscopic examination. However, there are no reports on the clinical application of ultrasonography using tissue Doppler imaging. In this review, we describe the pathophysiology and treatments for OD, introduce our novel US method to evaluate cervical esophageal motility, and then outline our clinical study examining the effects of capsaicin, a specific TRPV1 agonist, in older patients with OD.

Effectiveness of impedance parameters for muscle quality evaluation in healthy men

We investigated the relationship between impedance parameters and skeletal muscle function in the lower extremities, as well as the effectiveness of impedance parameters in evaluating muscle quality. Lower extremity impedance of 19 healthy men (aged 23-31 years) measured using the direct segmental multi-frequency bioelectrical impedance analysis were arc-optimized using the Cole-Cole model, following which phase angle (PA), [Formula: see text], and β were estimated. Skeletal muscle function was assessed by muscle thickness, muscle intensity, and isometric knee extension force (IKEF). IKEF was positively correlated with PA (r = 0.58, p < 0.01) and β (r = 0.34, p < 0.05) was negatively correlated with [Formula: see text] (r = - 0.43, p < 0.01). Stepwise multiple regression analysis results revealed that PA, β, and [Formula: see text] were correlated with IKEF independently of muscle thickness. This study suggests that arc-optimized impedance parameters are effective for evaluating muscle quality and prediction of muscle strength.

Motor activation is modulated by visual experience during cyclic gait observation: A transcranial magnetic stimulation study

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.

A novel fluoroscopic method for multidimensional evaluation of swallowing function

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: 20mL of pure water followed by 20mL 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.

Preventive Effects of Repetitive Peripheral Magnetic Stimulation on Muscle Atrophy in the Paretic Lower Limb of Acute Stroke Patients: A Pilot Study

Objective:

The aim of this study was to investigate the effect of repetitive peripheral magnetic stimulation (rPMS) on muscle atrophy prevention in the rectus femoris muscle (RF) of the paretic limb in acute stroke patients.

Methods:

Twelve acute stroke patients with a National Institute of Health Stroke Scale score >5 and a motor score of the paretic lower limb >2 at admission were divided into an intervention group (rPMS: mean age, 75±6.4 years) and a conventional care group (non-rPMS: mean age, 62±11.8 years). Baseline measurements were performed within 4 days of stroke onset. In the rPMS group, treatment was applied to the paretic thigh only for 2 weeks, 5 days a week, in addition to conventional care. The cross-sectional area (CSA) of the RF was assessed in both limbs using ultrasound at baseline and 2 weeks later. Data on patient characteristics were collected from the clinical records to assess correlations with the CSA rate of change.

Results:

Patients in the rPMS group were significantly older. Although the CSA of the RF did not change significantly on either side in the rPMS group, there was a significant decrease in the CSA on the paretic side in the non-rPMS group. However, no significant difference was observed in the CSA rate of change in the rPMS and non-rPMS groups. The CSA rate of change on the paretic side correlated negatively with age in the rPMS group.

Conclusions:

Our results suggest that rPMS prevents muscle atrophy more effectively in patients in their 60s than in patients more than 70 years old.

Premotor potential study in carpal tunnel syndrome

INTRODUCTION

Premotor potentials (PMPs) precede compound muscle action potentials evoked from the second lumbrical muscle after median nerve stimulation. Although PMP has been identified as a median sensory nerve action potential, few reports have documented the significance of PMP parameters for diagnosing carpal tunnel syndrome (CTS).

METHODS

We investigated the relationships between PMP parameters and results of 6 standard median nerve conduction studies in 74 CTS hands.

RESULTS

Significant correlations were noted in all comparisons. PMP conduction velocity was strongly correlated with the sensory conduction velocity between wrist and digit 2 (r(2) = 0.91). Moreover, PMP parameters were significantly correlated with neurophysiological severity of CTS.

CONCLUSION

Measuring PMP parameters with a second lumbrical-interosseous study may be useful for diagnosing CTS.

The origin of the premotor potential recorded from the second lumbrical muscle in normal man

OBJECTIVE

When recording with a palm electrode, a premotor potential precedes the compound muscle action potential (CMAP), evoked from the second lumbrical (2L) muscle following median nerve stimulation. The purpose of this study was to determine the origin of the premotor potential from the 2L.

METHODS

We recorded potentials with multi-channel electrodes in the palm and finger in a bipolar or referential manner, stimulating the second digit or median nerve at the wrist.

RESULTS

We recorded the traveling nearfield sensory nerve action potential (SNAP) and stationary negative potential in the palm. The peak latency of the stationary negative potential was the same as the one of the near-field potential of the digital sensory fibers at the base of the second finger. The onset of the premotor potential from the 2L muscle is aligned to the palmar SNAP in a bipolar manner by antidromic stimulation.

CONCLUSIONS

We conclude that the premotor potential from the 2L muscle is composed of a SNAP arising from antidromically activated palm sensory branches and a far-field potential generated by the median digital nerve fibers as they pass from the palm into the second finger.

SIGNIFICANCE

Our results might be useful for evaluating the 2L-interossei test for diagnosing carpal tunnel syndrome.

Enhancement of Facilitation Training for Aphasia by Transcranial Direct Current Stimulation

We aimed to enhance the performance of naming and sentence production in chronic post-stroke aphasia by tablet-based language training combined with transcranial direct current stimulation (tDCS) conducted on non-consecutive days. We applied a deblocking method involved in stimulation–facilitation therapy to six participants with chronic aphasia who performed naming and sentence production tasks for impaired modalities, immediately after a spoken-word picture-matching task for an intact modality. The participants took part in two conditional sessions: a tDCS condition in which they performed a spoken word-picture matching task while we delivered an anodal tDCS over the left inferior frontal cortex; and a sham condition in which sham stimulation was delivered. We hypothesized that, compared with the sham stimulation, the application of anodal tDCS over the left inferior frontal cortex during the performance of tasks requiring access to semantic representations would enhance the deblocking effect, thereby improving the performances for subsequent naming and sentence production. Our results showed greater improvements 2 weeks after training with tDCS than those after training with sham stimulation. The accuracy rate of naming was significantly higher in the tDCS condition than in the sham condition, regardless of whether the words were trained or not. Also, we found a significant improvement in the production of related words and sentences for the untrained words in the tDCS condition, compared with that found pre-training, while in the sham condition we found no significant improvement compared with that found pre-training. These results support our hypothesis and suggest the effectiveness of the use of tDCS during language training on non-consecutive days.

Efficacy of soft palatal augmentation prosthesis for oral functional rehabilitation in patients with dysarthria and dysphagia: a protocol for a randomised controlled trial

INTRODUCTION

Palatal augmentation prosthesis (PAP) is used in patients with articulation and swallowing disorders caused by postoperative loss of tongue tissue due to tongue cancer, cerebrovascular disease sequelae and age-related hypofunction. We have previously reported a newly designed soft PAP fabricated using an thermoplastic material that is particularly appropriate for early intervention. However, the effect of soft PAP on oral function improvement remains to be elucidated. The aim of this study is to investigate whether soft PAP can improve dysarthria and dysphagia occurring as cerebrovascular disease sequelae.

METHODS AND ANALYSIS

This prospective, randomised, controlled trial will compare the immediate and training effects of rehabilitation using soft PAP with those of rehabilitation without using it. Primary outcomes are the single-word intelligibility test score and pharyngeal transit time (PTT). Secondary outcomes are tongue function (evaluated based on maximum tongue pressure, repetitions of tongue pressure and endurance of tongue pressure), articulation function (evaluated based on speech intelligibility, oral diadochokinesis, Voice-Related Quality of Life (V-RQOL)) and swallowing function (evaluated using Eating Assessment Tool-10). The study results will help determine the efficacy of Soft PAP in improving functional outcomes of word intelligibility and PTT. We hypothesised that early rehabilitation using Soft PAP would more effectively improve articulation and swallowing function compared with conventional rehabilitation without using soft PAP.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Okayama University Certified Review Board. The study findings will be published in an open access, peer-reviewed journal and presented at relevant conferences and research meetings.

TRIAL REGISTRATION NUMBER

jRCTs062200054.

Two Cases of Doppler Sonography for Intraneural Vascularity of Ulnar Neuropathy at the Elbow: Before and After Surgery

The finding of an intraneural blood flow (IBF) signal on Doppler sonography (DS) in non-surgical cases is interpreted in several ways and usually represents a pathologic condition with entrapment neuropathy. There have been no reports of the IBF signal on DS after surgery for ulnar neuropathy at the elbow (UNE). IBF was investigated before and after surgery in two cases diagnosed with UNE before surgery and confirmed after surgery. Both underwent electrodiagnostic (EDX) studies, grey scale sonography (GS), and DS before and after surgery and were diagnosed as having UNE by EDX study and GS. On DS, an IBF signal was not detected in both cases before surgery. After surgery, both cases improved their clinical and EDX findings, and an IBF signal and pulsatility were detected on DS. With respect to vascular problems, recovering venous and arterial blood supplies and dilated vessels would show much more blood flow during recovery of the affected ulnar nerve site following decompression surgery. The IBF signal would not always implicate pathology. When assessing recovery from UNE after surgery, it may be useful to evaluate intraneural vascularity at the affected site with DS.

Virtual reality-based myoelectric prosthetic control training: Effects of action observation and motor imagery with visual feedback of electromyographic signals

BACKGROUND

Conventional myoelectric prostheses (myo-prostheses) training involves repetitive grasping and manipulation training, which requires considerable training time. It is necessary to develop a short and efficient myo-prostheses training. This study aimed to verify the immediate and sustained effects of action observation and motor imagery (AOMI) using virtual reality (VR) on myo-prostheses control and clarify the effect of visual feedback of electromyogram (EMG) signals during AOMI using VR.

STUDY DESIGN AND METHODS

We evaluated 24 healthy right-handed individuals wearing a myo-prostheses simulator in their dominant hands. We divided participants into 3 groups: VR video observation with EMG presentation during manipulation (VR+), VR video observation without EMG presentation (VR), and control group. We evaluated prosthetic control skills using the Grasp Force Adjustment Test (GFAT) and Bowknot task immediately before and after AOMI and 1 week later. In addition, we evaluated the level of immersion during AOMI.

RESULTS

The rate of change in the GFAT 1 week after the intervention was significantly greater in the VR+ (P < 0.05, d = 1.32) and VR (P < 0.01, d = 2.34) groups than in the control group. Immersion was significantly higher in the VR+ and VR groups than in the control group. The condition and time required for GFAT had significant effects, although the post-hoc test showed no significant difference between VR+ and VR groups.

CONCLUSIONS

AOMI using VR had sustained effects on motor learning of myo-prosthetic control despite EMG presentation. Therefore, AOMI, using VR, manipulates prostheses once learned, and it might be used for future training of myo-prosthetic control.