Repetitive transcranial magnetic stimulation for lower extremity motor function in patients with stroke:a systematic review and network meta-analysis

Transcranial magnetic stimulation,a type of noninvasive brain stimulation,has become an ancillary therapy for motor function rehabilitation.Most previous studies have focused on the effects of repetitive transcranial magnetic stimulation(rTMS)on motor function in stroke patients.There have been relatively few studies on the effects of different modalities of rTMS on lower extremity motor function and corticospinal excitability in patients with stroke.The MEDLINE,Embase,Cochrane Library,ISI Science Citation Index,Physiotherapy Evidence Database,China National Knowledge Infrastructure Library,and ClinicalTrials.gov databases were searched.Parallel or crossover randomized controlled trials that addressed the effectiveness of rTMS in patients with stroke,published from inception to November 28,2019,were included.Standard pairwise meta-analysis was conducted using R version 3.6.1 with the“meta”package.Bayesian network analysis using the Markov chain Monte Carlo algorithm was conducted to investigate the effectiveness of different rTMS protocol interventions.Network meta-analysis results of 18 randomized controlled trials regarding lower extremity motor function recovery revealed that low-frequency rTMS had better efficacy in promoting lower extremity motor function recovery than sham stimulation.Network meta-analysis results of five randomized controlled trials demonstrated that highfrequency rTMS led to higher amplitudes of motor evoked potentials than low-frequency rTMS or sham stimulation.These findings suggest that rTMS can improve motor function in patients with stroke,and that low-frequency rTMS mainly affects motor function,whereas high-frequency rTMS increases the amplitudes of motor evoked potentials.More highquality randomized controlled trials are needed to validate this conclusion.The work was registered in PROSPERO(registration No.CRD42020147055)on April 28,2020.

How does anterior cruciate ligament reconstruction affect the functioning of the brain and spinal cord?A systematic review with meta-analysis

Objective:To examine the effect of anterior cruciate ligament(ACL)reconstruction on spinal-reflex and corticospinal excitability of the quadriceps muscle.Methods:A comprehensive electronic database search was performed to identify studies that objectively measured Hoffmann reflex to muscle response ratio,motor threshold,and motor evoked potentials after ACL reconstruction.Pooled standardized mean differences(SMDs)were computed using a random effects meta-analysis model.Results:A total of 13 studies were eligible for analysis.The Hoffmann reflex to muscle response ratio was significantly higher on both the reconstructed and non-reconstructed legs when compared with the healthy control leg(SMD=0.28,95%confidence interval(95%CI):0.08-0.49,p=0.006 and SMD=0.22,95%CI:0.04-0.40,p=0.016,respectively)but did not differ between legs(SMD=0.10,95%CI:-0.01 to 0.21,p=0.078).The motor threshold was significantly higher on both the reconstructed(SMD=0.76,95%CI:0.40-1.12,p<0.001)and non-reconstructed legs(SMD=0.47,95%CI:0.00-0.95,p=0.049)when compared with the legs of healthy controls.The reconstructed leg also had a higher motor threshold when compared with the non-reconstructed leg(SMD=0.20,95%CI:0.06-0.34,p=0.005).These changes were paralleled by bilateral reductions in quadriceps strength(ACL reconstructed:SMD=-0.78,95%CI:-1.07 to-0.49,p<0.001;non-reconstructed:SMD=-0.32,95%CI:-0.63 to-0.01,p=0.042)and quadriceps voluntary activation(ACL reconstructed:SMD=-0.73,95%CI:-0.97 to-0.50,p<0.001;non-reconstructed:SMD=-0.55,95%CI:-0.82 to-0.27,p<0.001)when compared with healthy controls.Conclusion:There is increased excitability of the spinal-reflex pathways and reduced excitability of the corticospinal pathways following ACL reconstruction.These changes are paralleled by reductions in quadriceps strength and voluntary activation,suggesting that rehabilitation interventions should focus on normalizing the excitability of neural pathways to effectively address quadriceps dysfunction after ACL reconstruction.

Postsynaptic Excitation of Prefrontal Cortical Pyramidal Neurons by Hypocretins/Orexins

Hypocretins/orexins are crucial for the regulation of wakefulness by the excitatory actions on multiple subcortical arousal systems. In prefrontal cortex,