Analysis of muscle synergy and gait kinematics during regain of gait function through rehabilitation in a monoplegic patient.

Purpose: We conducted muscle synergy and gait analyses in a monoplegic patient whose gait function improved through training, to explore the possibility of using these parameters as indicators of training. Case presentation: A 49-year-old male had monoplegia of the right lower limb caused by infarction of the left paracentral lobule. After 2 months of training, he was able to walk and returned to work. Methods: Consecutive analyses were done after admission. Muscle synergy analysis: during walking, surface electromyograms of gluteus maximus, quadriceps femoris, adductor femoris, hamstrings, tibialis anterior, medial/lateral gastrocnemius, and soleus on both sides were recorded and processed for non-negative matrix factorization (NNMF) analysis. Gait analysis: markers were placed at foot, and walking movements were video recorded as changes in position of the markers. Results: Compared with three muscle synergies detected on the non-paretic side, two muscle synergies were extracted on the paretic side at admission, and the number increased to three and then four with progress in rehabilitation training. Changes in weighting and activity of the muscle synergies were greater on the non-paretic side than on the paretic side. With training, the knee joint flexor and the ankle dorsiflexor activities on the paretic side and the gluteus maximus activity on the non-paretic side increased during swing phase as shown by weight changes of muscle synergies, and gait analysis showed increased knee joint flexion and ankle joint dorsiflexion during swing phase in the paretic limb. On the non-paretic side, however, variability of muscle activity was observed, and three or four muscle synergies were extracted depending on the number of strides analyzed. Conclusion: The number of muscle synergies is considered to contribute to motor control. Rehabilitation training improves gait by increasing the number of muscle synergies on the paretic side and changing the weights of the muscles constituting the muscle synergies. From the changes on the non-paretic side, we propose the existence of compensatory mechanisms also on the non-paretic side. In muscle synergy analysis, in addition to the filters, the number of strides used in each analysis set has to be examined. This report highlights the issues of NNMF as analytical methods in gait training for stroke patients.

Role of primary motor cortex in gait: automatic-voluntary dissociation seen in paretic leg of a patient who had a stroke.

Objective: To examine the role of primary motor cortex in gait through exploring the dissociation of impaired voluntary leg muscle contraction and preserved rhythmic activities during gait in a patient who had a stroke. Subject and methods: A 49-year-old man with an infarct in the primary motor cortex exhibited automatic-voluntary dissociation in the paretic leg. Functional studies were conducted using surface electromyography (EMG) and near-infrared spectroscopy (NIRS). Results: The patient was incapable of voluntary contraction of individual leg muscles on the paretic right side but was able to walk automatically while contracting those muscles rhythmically. Surface EMG confirmed the earlier findings objectively. The preserved automatic activities helped recovery of gait capability, but NIRS showed no functional recovery in the corresponding motor cortex during treadmill gait. We considered that the loss of voluntary leg muscle contraction and the preserved gait capacity in this patient represented a form of automatic-voluntary dissociation. Conclusions: The preserved gait capability suggests that the leg representation of the primary motor cortex may not play a major functional role in gait, but other components of the nervous system, including the spinal central pattern generator, would serve important functions to maintain gait capability.

False recognition/misidentification of unfamiliar person after cerebral infarction: A case report.

An 84-year-old man manifested false recognition/misidentification of unfamiliar person after cardiogenic cerebral infarction. He had good visual and hearing acuity, no hemianopsia, unilateral spatial neglect and visual object agnosia. However, he was unable to remember faces of his rehabilitation therapists, and repeatedly misidentified other patients' visitors and therapists as his family members and friends, without recognizing his mistakes. General cognitive function was preserved with Hasegawa dementia score-revised (HDS-R) 25/30 (cut-off score 20). In terms of recognition of faces, tasks not requiring recognition of facial identity, such as interpreting facial emotions, and gender and age assessment, were relatively preserved, but recognition of family members and celebrities was severely impaired, and matching unfamiliar faces was slightly impaired. Semantic information of family and friends was retained. Although his symptoms resembled associative prosopagnosia, they differed from general associative prosopagnosia in having phonagnosia. MRI lesions were localized in the frontal and temporal lobes including the right anterior temporal lobe, and not in the right occipital and temporal lobes considered to the lesion site of multimodal people recognition disorders manifesting inability of utilization of visual (face) and auditory (voice) cues for person identification. In addition to the facial cognitive impairment, impaired exploratory (monitoring) function of the frontal lobe on the temporal lobe may also contribute to the false recognition/misidentification of this case.

Releasing forced grasp reflex by use of concomitant imitation behaviour during rehabilitation of a stroke patient.

An 80-year-old woman had a stroke during treatment for diffuse large B cell lymphoma. She exhibited left hemispatial inattention, forced grasping with her left hand and moderate left hemiplegia. She always grasped the guard rail of the bed with her left hand, which prevented her from standing up and performing activities of daily living (ADL) centred on move and transfer operations. During a medical examination, she showed an imitation behaviour (IB), mimicking gestures visually presented by the examiner, such as holding up. By using her IB in rehabilitation training, flexor-dominated posture of the upper arm was gradually reduced and performance of ADL improved. Her brain lesion was localised in the right middle frontal gyrus. Based on our experience of concomitant appearance of forced grasping and IB in this case, the pathophysiological involvement of the lesion was discussed.

Preservation of explicit learning of visuomotor sequences during Parkinson's disease progression.

While motor learning approaches are effective in rehabilitating Parkinson's disease (PD) patients, many studies reported deficits in sequential motor learning in these patients. We hypothesised that preserved explicit learning of visuomotor sequences in PD patients contributed to the effectiveness of motor learning approaches. However, there are very few studies analysing explicit learning of visuomotor sequences during the progression of PD. We investigated this phenomenon in 23 patients with moderate to severe PD (Hoehn-Yahr stages II-IV) and 17 age-matched controls using sequential button-press tasks (2 × 5 task). We found (1) no significant differences in numbers of errors in the 2 × 5 task among control and PD groups. (2) There was a significant difference in response times while exploring correct sequences (ERT) among control and PD groups; ERTs in stage-IV patients tended to be longer than those of control and stage-II groups. (3) All four groups significantly improved their performance (i.e., reduced ERTs in the 2 × 5 task) with sequence repetition, although stage-III:IV patients were slower. Thus, even patients with severe PD can learn visual sequences and can translate them into visuomotor sequences (explicit visuomotor sequence learning), albeit slower than controls, providing evidence for effective motor learning approaches during rehabilitation of patients with advanced PD.

The Orphan Nuclear Receptor NR4A3 Is Involved in the Function of Dendritic Cells.

NR4A3/NOR1 belongs to the NR4A subfamily of the nuclear hormone receptor superfamily, which is activated in a ligand-independent manner. To examine the role of NR4A3 in gene expression of dendritic cells (DCs), we introduced NR4A3 small interfering RNA (siRNA) into bone marrow-derived DCs and determined the expression levels of mRNA and proteins of cytokines, cell surface molecules, NF-κB signaling-related proteins, and transcription factors. The expression level of NR4A3 was markedly upregulated by TLR-mediated stimulation in DCs. NR4A3 knockdown significantly suppressed LPS, CpG, or poly(I:C)-mediated upregulation of CD80, CD86, IL-10, IL-6, and IL-12. Proliferation and IL-2 production levels of T cells cocultured with NR4A3 knocked-down DCs were significantly lower than that of T cells cocultured with control DCs. Furthermore, the expression of IKKß, IRF4, and IRF8 was significantly decreased in NR4A3 siRNA-introduced bone marrow-derived DCs. The knockdown experiments using siRNAs for IKKß, IRF4, and/or IRF8 indicated that LPS-induced upregulation of IL-10 and IL-6 was reduced in IKKß knocked-down cells, and that the upregulation of IL-12 was suppressed by the knockdown of IRF4 and IRF8. Taken together, these results indicate that NR4A3 is involved in TLR-mediated activation and gene expression of DCs.

The Cognition of Maximal Reach Distance in Parkinson's Disease.

This study aimed to investigate whether the cognition of spatial distance in reaching movements was decreased in patients with Parkinson's disease (PD) and whether this cognition was associated with various symptoms of PD. Estimated and actual maximal reaching distances were measured in three directions in PD patients and healthy elderly volunteers. Differences between estimated and actual measurements were compared within each group. In the PD patients, the associations between "error in cognition" of reaching distance and "clinical findings" were also examined. The results showed that no differences were observed in any values regardless of dominance of hand and severity of symptoms. The differences between the estimated and actual measurements were negatively deviated in the PD patients, indicating that they tended to underestimate reaching distance. "Error in cognition" of reaching distance correlated with the items of posture in the motor section of the Unified Parkinson's Disease Rating Scale. This suggests that, in PD patients, postural deviation and postural instability might affect the cognition of the distance from a target object.

Functional difference between the proximal and distal compartments of the semitendinosus muscle.

[Purpose] The tendinous inscription divides the semitendinosus muscle into the proximal and distal compartments. It was hypothesized that there are functional differences between those compartments. [Subjects and Methods] Seven adult males performed knee flexion and hip extension in the prone position. An ultrasound device measured the decrease in the length of muscle fibers in the two compartments during these movements. The knee and hip joint angles were concurrently measured using a video camera. Pearson's correlation coefficients were calculated between the decrease in muscle fiber length in each compartment and joint angle. [Results] During knee flexion, decreased muscle fiber length was significantly correlated with increased knee flexion angle. During hip extension, there were no significant correlations for either compartment. Only the decrease in muscle fiber length in the distal compartment during hip extension tended to be negative; the other decreases in muscle fiber length tended to be positive. [Conclusion] Correlations did not reveal any functional differences. However, only the distal compartment elongated during hip extension. This result might show a functional difference and could be applied in clinical contexts during hip extension.

[Pathophysiological analysis of dropped head syndrome caused by various diagnoses - based on surface EMG findings and responses to physiotherapy].

Dropped head syndrome is seen in various diseases. We investigated its pathophysiological mechanisms with physical and radiological examination, surface EMG and responses to physiotherapy. Subjects had dropped head as a complaint, but their primary diagnoses were various. We investigated 16 cases: 5 cases of Parkinson disease, 5 cases of multiple system atrophy predominant parkinsonism, 3 cases of cervical spondylosis and 3 cases with other diagnoses. We found that patients had common findings such as bulging of cervical muscles, and tonic EMG activities mainly in the extensors in the sitting and standing position, but in the flexors of the neck only in the supine position. Of the 16 cases, 14 were treated with physiotherapy to improve the alignment of the pelvis and whole vertebral column; 6 of the 14 cases (63%) showed remarkable improvement. We conclude that the primary reason of dropped head syndrome is unknown in Parkinson disease and cervical spondylosis, but also that many of the patients have secondary changes in alignment of the skeletomuscular system which could be treated with physiotherapy.

Effect of vibration stimulation on dysbasia of spastic paraplegia in neuromyelitis optica: a possible example of neuronal plasticity.

We analysed the effect of vibration stimulation (VS) on dysbasia of neuromyelitis optica (NMO). The patient was a 36-year-old woman who was diagnosed with NMO and had difficulties in walking. VS was applied to the lower limb muscles on the left, more spastic, side with an ordinary vibrator. The performance of standing up and walking improved with VS. Even with improved performance after VS, the amount of surface EMG of the lower limbs did not increase as a whole, but the EMG patterns among the lower leg muscles changed remarkably. VS produced reciprocity within antagonistic muscles. Variability of EMG amplitudes decreased remarkably during the walking cycle, not only on the vibrated side, but also on the non-vibrated side. The effect lasted longer than several dozen minutes after the cessation of VS. We conjectured that central pattern generator (CPG) and neuronal plasticity were the result of VS.

Analysis of EMG signals of patients with essential tremor focusing on the change of tremor frequency.

Essential tremor is a disorder that causes involuntary oscillations in patients while engaging in actions or while maintaining a posture. ET patients have serious difficulties in performing activities of daily living such as eating food, drinking water, and writing. We have thus been developing an EMG-controlled exoskeletal robot to suppress tremors. The EMG signal of ET patients involves a mix of voluntary movement and tremor signals. To control the exoskeletal robot accurately, tremor signals must be removed from the patient's EMG signal. To date, we have been developing a filter to remove tremor signals from the patient's EMG. The design of this filter was based on the hypothesis that the rectified tremor signals are able to be approximated by a powered sine wave. This filter was found to have a large effect on removing tremor signals. However, tremor signals are generated both while performing voluntary movement and while maintaining a posture, and the filter was attenuating both signals. To control this robot accurately, the signal generated while performing voluntary movement is expected not to be attenuated. To accomplish this, we try to use a parameter that reflects a state of the patient's movement, performing a voluntary movement or maintaining a posture, as a switch to activate the powered sine filter. This paper provides an analysis of the favorable parameters. We focus on two parameters: the peak-to-peak interval of the rectified EMG signal, and the interval of the flat and low amplitude area of the rectified EMG signal. Through evaluation, it is affirmed that both parameters change with the state of the patient's movement. However, the latter parameter is superior to the former in terms of variability, which indicates that the interval of the flat and low amplitude area of the rectified EMG signal is a more favorable parameter to promote control of the exoskeletal robot. As a future work, we will mount the parameter to the algorithm and evaluate the robotic system.

Filtering essential tremor noise on surface EMG based on squared sine wave approximation.

Essential Tremor (ET) refers to involuntary movements of a part of the body. ET patients have serious difficulties in performing daily living activities. Our ultimate goal is to develop a system that can enable ET patients to perform daily living activities. We have been developing an exoskeleton robot for ET patients. We make use of the electromyogram (EMG) signal to control this robot. However, the EMG signal of ET patients contains not only signals from voluntary movements but also noise from involuntary tremors. In this paper, we focus on developing a signal processing method to suppress tremor noise present in the surface EMG signal. The proposed filter detected attenuation ratio by the correlation between the last EMG data and one period squared sine wave. The filtered EMG signals indicated that essential tremor noise of the elbow flexed posture while holding a water-filled bottle was suppressed. In addition, voluntary information was less affected by the filter. Welch's t-value test confirmed that ease of extraction of voluntary movement was increased by the proposed filter.

[Neural mechanisms underlying spasticity].

Considering the various studies conducted on spasticity, it is quite evident that the signs and symptoms of this disorder vary. In some cases of spasticity, spasms may be noted. An increase in velocity-dependent stretch reflexes has been proposed as a cardinal feature of spasticity. There are 2 possible mechanisms underlying increased stretch reflex of spasticity: one is the changes in gamma innervations and the other is one the changes in spinal motoneurons. Changes in gamma innervations for spasticity are not evident while the muscle are at rest. On the other hand, changes are clear in normal subjects during voluntary contraction of muscles, but not in sbjects with spasticity. We have discussed the changes in membrane properties caused by presynaptic inhibition, reciprocal Ia inhibitory function, recurrent inhibition, and autogenic Ib inhibition as the other candidate spinal mechanisms for spasticity.

[Validation of the Japanese version of the Parkinson's Disease Questionnaire].

UNLABELLED: The PDQ-39 (Parkinson's Disease Questionnaire-39) is a specific quality-of-life (QOL) scale for patients with Parkinson's disease (PD). It evaluates the dysfunction of daily living and quality of life. We developed the Japanese-translated version of PDQ-39 and examined the validity of the PDQ-39 in Japanese PD patients. SUBJECTS: A total of 156 patients with PD were studied (age 35-86 years, Hoehn-Yahr stage 1 to 4). None of the patients had dementia. METHODS: Semi-structured interviews were conducted by one trained interviewer. The PDQ-39, SF-36 (36-item short form of the Medical Outcome Study questionnaire), EQ5D (Euro Qol), and NAS-J (Nottingham Adjustment Scale Japanese version) were used for evaluation. The attending physician of each patient rated the patient's condition by using the UPDRS (Unified Parkinson's Disease Rating Scale). RESULTS: Exploratory factor analysis, Cronbach alpha, and construct validity were fair, and there were significant correlations between the results of the PDQ-39 and the corresponding parts of the UPDRS and SF-36, and the Hoehn-Yahr stage, respectively. CONCLUSION: The Japanese version of the PDQ-39 is valuable for evaluating the QOL of Japanese patients with PD. Results of comparison of PDQ-39 with other scales of the QOL such as NAS-J suggest the possibility that acceptance of the disease and feelings of self-achievement improve the QOL of patients with Parkinson's disease.