Characterization of temporal and intensity parameters of early postural adjustment phase during gait initiation in stroke patients / 中国组织工程研究

BACKGROUND:Early postural adjustments serve as preparatory measures for forthcoming actions or potential disruptions in posture,thereby facilitating improved movement execution and mitigating destabilizing effects caused by posture interference. OBJECTIVE:To investigate the characteristics of temporal and intensity parameters of key lower limb muscles during early postural adjustment phase when stroke patients with varying levels of balance initiate walking at a self-selected comfortable pace. METHODS:The characteristics of early postural adjustments in 16 stroke patients were observed.Sixteen patients were divided into a non-fall group(n=8)and a fall group(n=8)based on the history of falls and Berg Balance Scale scores.Noraxon inertial sensors and Noraxon Ultium EMG wireless surface electromyography were utilized to collect body kinematic data and surface electromyography data during gait initiation.Muscle activation time and activation sequence of six key muscles in the lower limbs(tibialis anterior,medial and lateral gastrocnemius,rectus femoris,lateral femoris and biceps femoris muscles)during the early postural adjustment phase,as well as normalized electromyography integral values for the four time windows(each 150 ms)before gait initiation,were analyzed. RESULTS AND CONCLUSION:Stroke patients with a history of falls exhibited earlier activation times for the six key muscles in the lower limbs during gait initiation compared with those in the non-fall group.The fall group demonstrated significantly earlier activation times for tibialis anterior,lateral head of gastrocnemius,and vastus lateralis(P<0.01,P<0.05).In contrast,the non-fall group displayed a consistent pattern of activating extensor muscles before flexor muscles,with thigh muscle activation preceding calf muscle activation.However,in the fall group,calf extensor muscle activation occurred prior to thigh extensor muscle activation,and the vastus lateralis was activated even earlier.The tibialis anterior was the last activated muscle in both groups.Specifically during T3(>-300 to-150 ms),the tibialis anterior exhibited significantly higher activity in the fall group compared with the non-fall group(P<0.05),while the lateral head of gastrocnemius demonstrated significant inhibition during T3(P<0.05)and the medial head of gastrocnemius showed significant inhibition during both T3 and T4(>-150 to 0 ms)stages compared with the non-fall group(P<0.01,P<0.05).To conclude,stroke patients with varying balance abilities employ distinct early postural adjustment strategies prior to stepping,as evidenced by differences in muscle activation timing,recruitment order,and muscle activity amplitude.Patients at a high risk of falling exhibit prolonged duration of early postural adjustment and delayed initiation of gait,indicating earlier activation of the tibialis anterior muscle and inhibition of gastrocnemius muscle activity.These delays in gait initiation and variations in muscle recruitment strategies may contribute to unstable posture and an increased susceptibility to falls.

Effect of transcranial direct current stimulation combined with robotic therapy on the rehabilitation of upper-limb motor function of hemiplegic stroke patients / 国际生物医学工程杂志

Objective:To investigate the effect of cathodic transcranial direct current stimulation (ctDCS) combined with upper limb robot therapy (RT) on the rehabilitation of upper limb motor function in stroke patients.Methods:Forty patients with stroke hemiplegia who met the enrollment criteria were randomly divided into a pseudo-stimulation group ( n = 20) and a stimulation group ( n = 20). In addition to conventional treatment in both groups, ctDCS + RT was used in the stimulation group, and sham stimulation + RT was used in the sham-stimulation group. Treatment was performed 10 times, 5 times per week, for 30 minutes each time. Patients in both groups were evaluated before, during, and after treatment using the Brunnstrom Staging Scale, the Modified Barthel Index (MBI) scale, and the Modified Ashworth Scale (MAS), respectively. Results:Compared with the same group before treatment, there were statistically significant differences in Brunnstrom’s rating grade Ⅳ for upper limbs and hands in both groups during and after treatment (all P < 0.05). Compared with the same group during treatment, there were statistically significant differences in Brunnstrom’s rating grade Ⅳ for upper limbs and hands in both groups after treatment (all P < 0.05). MBI scores were higher in two groups during and after treatment compared to the same group before treatment (all P < 0.05). MBI scores were higher in two groups after treatment compared to the same group during treatment (all P < 0.05). The MBI scores after treatment in the stimulation group were higher than those in the pseudo-stimulation group ( P < 0.05). The MAS scores of elbow flexion grade 2 and extension grade 4 and shoulder flexion grade 2, extension grade 2, adduction grade 2, and abduction grade 2 were lower in both groups after treatment compared with the same group before treatment (all P < 0.05). Conclusions:Cathodic transcranial direct current stimulation combined with robotic therapy can effectively promote upper limb motor function rehabilitation in stroke patients and is superior to upper limb robotic therapy alone.

Research on electroencephalogram power spectral density of stroke patients under transcranial direct current stimulation / 生物医学工程学杂志

Transcranial direct current stimulation (tDCS) has become a new method of post-stroke rehabilitation treatment and is gradually accepted by people. However, the neurophysiological mechanism of tDCS in the treatment of stroke still needs further study. In this study, we recruited 30 stroke patients with damage to the left side of the brain and randomly divided them into a real tDCS group (15 cases) and a sham tDCS group (15 cases). The resting EEG signals of the two groups of subjects before and after stimulation were collected, then the difference of power spectral density was analyzed and compared in the band of delta, theta, alpha and beta, and the delta/alpha power ratio (DAR) was calculated. The results showed that after real tDCS, delta band energy decreased significantly in the left temporal lobes, and the difference was statistically significant ( P < 0.05); alpha band energy enhanced significantly in the occipital lobes, and the difference was statistically significant ( P < 0.05); the difference of theta and beta band energy was not statistically significant in the whole brain region ( P > 0.05). Furthermore, the difference of delta, theta, alpha and beta band energy was not statistically significant after sham tDCS ( P > 0.05). On the other hand, the DAR value of stroke patients decreased significantly after real tDCS, and the difference was statistically significant ( P < 0.05), and there was no significant difference in sham tDCS ( P > 0.05). This study reveals to a certain extent the neurophysiological mechanism of tDCS in the treatment of stroke.

The clinical efficacy of treating autistic children using transcranial direct current stimulation / 中华物理医学与康复杂志

Objective:To investigate the effect of transcranial direct current stimulation (tDCS) on the behavior and the mismatch negativity (MMN) component of the auditory evoked potential of autistic children.Methods:Thirty-four autistic children were randomly divided into an anode stimulation group ( n=19) and a pseudo-stimulation group ( n=16). Both groups were given one hour of routine rehabilitation five times a week for 4 weeks, while the anode stimulation group was additionally provided with 20 minutes of tDCS 3 times a week. Before and after the treatment, both groups′ behavior was evaluated by using autism behavior checklist (ABC) as well as any changes in MMN of the auditory evoked EEG signals. Results:There were no significant differences between the two groups in any of the measurements before the treatment. Afterwards behavior had improved significantly in both groups, with significantly greater improvement in the stimulated group. In the stimulated group the average MMN amplitude had increased significantly and the average latency had decreased significantly. However, no such significant changes were observed in the pseudo-stimulation group. There was a significant linear correlation between the changes in the incubation period of MMN components and the improvements in ABC, vestibular functioning, tactile defense and proprioception.Conclusion:Anodal tDCS combined with conventional rehabilitation therapy can effectively increase the MMN amplitude and shorten the latency in autistic children, improving their brain function.

Research on characteristics of brain functional network in stroke patients during convalescent period under transcranial direct current stimulation / 生物医学工程学杂志

Transcranial direct current stimulation (tDCS) is an emerging non-invasive brain stimulation technique. However, the rehabilitation effect of tDCS on stroke disease is unclear. In this paper, based on electroencephalogram (EEG) and complex network analysis methods, the effect of tDCS on brain function network of stroke patients during rehabilitation was investigated. The resting state EEG signals of 31 stroke rehabilitation patients were collected and divided into stimulation group (16 cases) and control group (15 cases). The Pearson correlation coefficients were calculated between the channels, brain functional network of two groups were constructed before and after stimulation, and five characteristic parameters were analyzed and compared such as node degree, clustering coefficient, characteristic path length, global efficiency, and small world attribute. The results showed that node degree, clustering coefficient, global efficiency, and small world attributes of brain functional network in the tDCS group were significantly increased, characteristic path length was significantly reduced, and the difference was statistically significant (

Research progress of transcranial direct current stimulation and robotic therapy for the impaired upper limb motor function in stroke patients / 国际生物医学工程杂志

The upper limb dysfunction after stroke has a high incidence,and is difficult to recovery,which seriously affects the patients' activities of daily living and the quality of life.Scholars have been exploring new and effective rehabilitation strategies for upper limb dysfunction after stroke.Transcranial direct current stimulation (tDCS),a typical form of non-invasive brain stimulation,is widely used in upper limb function rehabilitation by modulating the excitability of the cerebral cortex to improve motion performance.Some results showed that tDCS combined with repetitive rehabilitation training can significantly improve the motion function of stroke patients.Robotic therapy (RT) provides high-intensity,repetitive motion therapy that meets the training needs of patients at different levels.Therefore,tDCS combined with RT can effectively enhance the upper limb function rehabilitation effect of stroke patients.In this paper,the research status of tDCS combined with RT in the treatment of upper limb function after stroke were reviewed such as target patients,treatment methods,rehabilitation effects,combination methods,etc.The research trends and future development ideas in this field were discussed.

Research progress of brain-computer interface technology for the rehabilitation of the upper limb motor function after stroke / 国际生物医学工程杂志

The upper limb dysfunction resulted from stroke has a high incidence and is hard to recover,seriously affecting the daily life and life quality of patients.The nerve tissue damage caused by stroke usually leads to the injuries of movement,sensory,cognitive and etc.The effective rehabilitation therapy can promote the rebuilding of the surviving cranial nerves to enhance the function and ability.As a modem intelligent nerve rehabilitation technology,brain-machine interface (BCI) directly builds the exchange channel between the brain and the surrounding environment.BCI extracts the brain's neural activity information,and transfers into the command to drive external equipment.BCI does not rely on the peripheral nerve system and muscle tissue.BCI technology is well suited for neurological rehabilitation training,because the repeated training associated with external equipments and BCI feedback can induce a normal exercise mode,indirectly induced the generation of normal brain signal,and promote brain remodeling,so that improve the patient's athletic ability and exercise control level.In this paper,the research progress of BCI technology for the rehabilitation of the upper limb motor function after stroke was reviewed,including the application,the efficacy and the existing limitations.

Sample entropy analysis of EEG in ischemic stroke patients / 国际生物医学工程杂志

Objective To explore the nonlinear complexity characteristics of electroencephalogram (EEG) in ischemic stroke patients with different course. Methods Sample entropy of all bands of EEG signals in 20 ischemic stroke patients and 10 healthy controls was extracted and analyzed using statistical analysis methods. Results The full-band EEG in sample entropy of stroke patients was significantly lower than that of healthy controls in most locations. Theα-band sample entropy of different course had significant differences in the frontal, temporal and occipital lobe (P<0.05), and the parameters had significant negative linear correlation with the post-stroke time in some locations. Conclusions There is an abnormal neural electrical activity in post-stroke patients. It is feasible to detect the aberrant EEG complexity using sample entropy, which is worth of further research.

Diagnosis and treatment on normotensive pheochromocytomas / 中华泌尿外科杂志

Objective To discuss the diagnosis and treatment of normotensive pheochromocyto-ma. Methods The clinical data of 22 patients with normotensive pheochromocytoma were reviewed. Inclusion criteria for normotensive pheochromocytoma were no previous history of hypertension and episode of symptoms suggesting high blood pressure. The blood pressure on admission was 90-130/ 60-90 mm Hg with an average of 113/72 mm Hg. Seven patients were found adrenal mass by routine ultrasonic examination. Twelve patients presented with superior abdominal or flank pain. Four pa-tients were present with fatigue, and 2 patients had fever. Headache and palpitation were found in 1 patient. Most of patients were present with large and round mass with low density area in the center of the tumor by uhrosonography and CT. Four patients had elevated level of plasma epinephrine and nor-epinephrine. 24 hours urine CA and VMA were elevated in 5 and 4 patients respectively. Seven pa-tients were prepared with infusion preoperatively to expand intravascular volume, and 2 patients were given prazosin 1.5 mg/d for 5 to 7 days. Results During the operation, seventeen patients had ele-vated blood pressure and 5 patients had no changed. One of seven patients with preoperative prepara-tion had obvious hypertension during operation, and 11 of 15 patients without preoperative preparation had obvious hypertension. The tumors were removed successfully in 21 patients. All the patients were diagnosed pheochromocytoma pathologically. Twenty-one patients had normal blood pressure with no recurrence during the follow-up from 1 month to 7 years. Conclusions The patients with normotensive pheochromocytomas may have lower catecholamine in their plasma and urine. The application of α-blockers and the expanding intravascular volume before operation could be important for the patients safe.

?_2-AR gene cloning from human detrusor cell and the construction of its antisense eukaryotic expression vector / 中华泌尿外科杂志

Objective To clone human beta-2 adrenoceptor gene from human bladder smooth muscle and to construct its antisense eukaryotic expression vector. Methods The ?_2-AR full length cDNA was cloned from human detrusor cells through RT-PCR and subcloned into clone vector (pUC18).The objective gene was then cut from ClaⅠ/HindⅢ sites of pUC18 with restriction endonulcease and subcloned into pLNCX vector in trans-direction.Finally the constructed ?_2-AR gene antisense expresstion vector was identified through restriction endonuclease analysis and sequencing. Results The sequence of cloned ?_2-AR full length cDNA was certified by comparison with the database of the Genebank.The constructed antisense eukaryotic expression vector was proved to be same with designed by restriction endonuclease analysis and sequencing. Conclusions ?_2-AR full length cDNA was cloned and its antisense eukaryotic expression vector was successfully constructed.This technique establishs the foundation for the further research on drug treatment of bladder dysfunction.