Impact of Repetitive Transcranial Magnetic Stimulation to the Cerebellum on Performance of a Ballistic Targeting Movement.

This study aimed to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) of the cerebellum on changes in motor performance during a series of repetitive ballistic-targeting tasks. Twenty-two healthy young adults (n = 12 in the active-rTMS group and n = 10 in the sham rTMS group) participated in this study. The participants sat on a chair in front of a monitor and fixed their right forearms to a manipulandum. They manipulated the handle with the flexion/extension of the wrist to move the bar on the monitor. Immediately after a beep sound was played, the participant moved the bar as quickly as possible to the target line. After the first 10 repetitions of the ballistic-targeting task, active or sham rTMS (1 Hz, 900 pulses) was applied to the right cerebellum. Subsequently, five sets of 100 repetitions of this task were conducted. Participants in the sham rTMS group showed improved reaction time, movement time, maximum velocity of movement, and targeting error after repetition. However, improvements were inhibited in the active-rTMS group. Low-frequency cerebellar rTMS may disrupt motor learning during repetitive ballistic-targeting tasks. This supports the hypothesis that the cerebellum contributes to motor learning and motor-error correction in ballistic-targeting movements.

Changes in the cortical silent period during force control.

PURPOSE: The contribution of gamma-aminobutyric acidergic inhibitory neural circuits in the primary motor cortex, as estimated by the cortical silent period, during weak and strong force output has not been defined. The aim of this study was to investigate whether cortical silent period is modulated with change from weak to strong force control. MATERIALS AND METHODS: Eleven healthy right-handed adults participated in this study. With the aid of visual feedback, participants were asked to control the force of abduction of the right index finger to 10%, 20%, 40%, 60%, 80%, and 100% of the maximum voluntary contraction. Single pulse transcranial magnetic stimulation was delivered to the left primary motor cortex region during force control tasks. The averaged actual force output level, background electromyography amplitude, and cortical silent period duration were compared between conditions, and correlation analysis was conducted. RESULTS: There were significant main effects of target force on background electromyography, and cortical silent period duration; with increased force, the actual force output level and background electromyography gradually increased, while cortical silent period duration gradually decreased. There were significant negative correlations between cortical silent period and force and cortical silent period and background electromyography. CONCLUSIONS: These findings indicate that the excitability of gamma-aminobutyric acidergic inhibitory neural circuits in primary motor cortex decreases in response to increased force output, mediated via increased corticospinal and motoneuron excitability. These results may facilitate understanding of the role of the gamma-aminobutyric acidergic circuit in primary motor cortex in force control, as well as of the mechanism underlying motor dysfunction in stroke-induced palsy, dystonia, and cerebellar ataxia.

Do changes in spinal reflex excitability elicited by transcranial magnetic stimulation differ based on the site of cerebellar stimulation?

PURPOSE: The present study aimed to investigate whether spinal reflex excitability is influenced by the site of cerebellar transcranial magnetic stimulation (C-TMS). MATERIALS AND METHODS: Fourteen healthy volunteers (mean age: 24.6 ± 6.6 years [11 men]) participated. Participants lay on a bed in the prone position, with both ankle joints fixed to prevent unwanted movement. Right tibial nerve stimulation was provided to elicit the H-reflex in the right soleus muscle. Conditioning transcranial magnetic stimulation (TMS) was delivered at one of the following sites 110 ms prior to tibial stimulation: right, central, or left cerebellum; midline parietal (Pz) region; or sham stimulation. A total of 10 test trials were included for each condition, in random order. The unconditioned and conditioned H-reflexes were measured during random inter-test trials, and the cerebellar spinal facilitation (CSpF) ratios for each site were calculated (the ratio of conditioned to unconditioned H-reflexes). CSpF ratios were compared among TMS sites. RESULTS: CSpF ratios were significantly higher at cerebellar sites than at the Pz site or during sham stimulation. However, there was no significant difference in CSpF ratio among cerebellar sites. CONCLUSIONS: TMS conditioning over any part of the cerebellum facilitated the excitability of the spinal motoneuron pool. Facilitation of the H-reflex due to C-TMS may involve the effects of the bilateral descending tract of the spinal cord on the spinal motoneuron pool. Alternatively, direct brainstem stimulation may have activated portions of the bilateral descending tract of the spinal cord.

Gaze stabilization exercises derive sensory reweighting of vestibular for postural control.

[Purpose] The aim of this study was to investigate whether gaze stabilization exercise derives sensory reweighting of vestibular for upright postural control. [Subjects and Methods] Twenty-three healthy volunteers participated in this study. The center of pressure of the total trajectory length was measured before (pre), immediately after (post), and 10 min after (post10) gaze stabilization exercise, in the static standing position, with the eyes open or closed, on the floor or on foam rubber. The sensory contribution values of the visual, somatosensory, and vestibular systems were calculated using center of pressure of the total trajectory length value in these measuring conditions. [Results] The center of pressure of the total trajectory length on foam rubber in post and post10 were significantly lower than that in the pre. The sensory contribution values of vestibular in post10 stages were significantly higher than that in pre-stage. [Conclusion] Gaze stabilization exercise can improve the static body balance in a condition that particularly requires vestibular function. The possible mechanism involves increasing sensory contribution of the vestibular system for postural control by the gaze stabilization exercise, which may be useful to derive sensory reweighting of the vestibular system for rehabilitation.

Abnormal bias in subjective vertical perception in a post-stroke astasia patient.

[Purpose] Post-stroke astasia is an inability to stand without external support despite having sufficient muscle strength. However, the dysfunction underlying astasia is unclear. We tested the hypothesis that astasia is the result of an abnormal bias in vertical perception, especially subjective postural vertical (SPV), mediated by somatosensory inputs. [Subjects and Methods] A patient with a right posterolateral thalamus hemorrhage had a tendency to fall toward the contralesional side during standing after 8 weeks of treatment. SPV, standing duration, and physical function were evaluated before and after a 1 week standard rehabilitation baseline period, and after a 1 week intervention period, where standing training requiring the patient to control his body orientation in reference to somatosensory inputs from his ipsilateral upper limb was added. [Results] SPV was biased toward the contralesional side before and after the 1 week baseline period. However, SPV improved into the normal range and he could stand for a longer duration after the intervention period. [Conclusion] This case suggests that abnormal SPV is one of the functional mechanisms underlying astasia, and it indicates the effectiveness of standing training with somatosensory information to improve abnormal SPV and postural disorders.

Prediction of destination at discharge from a comprehensive rehabilitation hospital using the home care score.

[Purpose] This study investigated whether it is possible to predict return to home at discharge from a rehabilitation hospital in Japan using the home care score of patients with cerebrovascular or osteoarticular disease and low activities of daily living at admission. [Subjects and Methods] The home care score and functional independent measurement were determined for 226 patients at admission and at discharge from five hospitals, and receiver operating characteristic analyses were conducted. [Results] The home care score cutoff point for the prediction of return to home at admission and at discharge was 11, and the area under the curve was more than 0.8. The area under the curve of the home care score was 0.77 for patients with low activities of daily living and within this group, the probability of return to home was approximately 50%, as predicted by the functional independent measurement. The home care score increased after receiving intervention at a rehabilitation hospital. [Conclusion] The home care score is useful for the prediction of return to home from a rehabilitation hospital, although prediction using the functional independent measurement is difficult for patients with low activities of daily living. Moreover, comprehensive interventions provided by the rehabilitation hospitals improve the ability to provide home care of the patient's family, which is assessed by the home care score.

Tonic suppression of the soleus H-reflex during rhythmic movement of the contralateral ankle.

[Purpose] We investigated the effect of rhythmic ankle movement on the contralateral soleus H-reflex. The H-reflex was evoked from the right soleus muscle. [Subjects and Methods] Healthy humans rhythmically moved the left ankle (movement condition) or held the left ankle stationary (stationary condition) at one of three positions corresponding to the ankle positions at which the H-reflex was evoked in the movement condition. The background electromyographic amplitude in the right soleus muscle was maintained at 10% of the maximum voluntary contraction level, and that in the right tibialis anterior muscle was matched between the stationary and movement conditions. [Results] The soleus H-reflex was suppressed throughout all phases of contralateral rhythmic ankle movement. [Conclusion] Rhythmic movement of the contralateral joint suppresses the H-reflex in the muscle that is the prime mover of the joint homologous to the rhythmically moving joint. This inhibitory mechanism may be activated during unilateral rhythmic movement to isolate the motor control of the moving ankle from that of the contralateral stationary ankle.

Revision of the predictive method improves precision in the prediction of stroke outcomes for patients admitted to rehabilitation hospitals.

[Purpose] The purpose of this study was to confirm the accuracy of a revised method for predicting the Functional Independence Measure (FIM) at discharge when stroke patients are first admitted to a rehabilitation hospital. [Subjects and Methods] The predictive equation with logarithmic trend line was calculated based on the total score of the FIM at admission and discharge in 93 patients with cerebral infarction (CI) and 60 patients with intracerebral hemorrhage (ICH). In other patients with CI or ICH (validation group), the differences between the actual FIM and the predicted FIM at discharge calculated by the CI or ICH equation and the combined (CI + ICH) equation, as well as by the CI or ICH equation and combined equation used in a previous study, were calculated. [Results] The multiple correlation coefficients of the CI equation, ICH equation, and combined equation were 0.87, 0.71, and 0.8. The residual of the actual FIM and predicted FIM at discharge calculated by the CI equation was the smallest in the CI validation group. In the ICH validation group, the residual calculated for ICH patients alone was smaller than that calculated by the previous ICH equation. [Conclusion] This easy-to-use method using a new equation for prediction was more precise than the previous equation. Therefore, we should revise the equation for predicting stroke patient outcome strata according to data from within the governing medical administration system.

The Neurorehabilitation of Neurological Movement Disorders Requires Rigorous and Sustained Research.

Movement disorders that stem from neurological conditions such as stroke, cerebral palsy, multiple sclerosis (MS), Parkinson's disease (PD), and spinocerebellar degeneration (SCD) can significantly impair a person's activities of daily living (ADL) [...].

Repetitive transcranial magnetic stimulation focusing on patients with neuropathic pain in the upper limb: a randomized sham-controlled parallel trial.

This study aimed to evaluate the efficacy and safety of navigation-guided repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex in patients with neuropathic pain in the upper limb. This randomized, blinded, sham-controlled, parallel trial included a rTMS protocol (10-Hz, 2000 pulses/session) consisting of five daily sessions, followed by one session per week for the next seven weeks. Pain intensity, as well as pain-related disability, quality of life, and psychological status, were assessed. For the primary outcome, pain intensity was measured daily using a numerical rating scale as a pain diary. Thirty patients were randomly assigned to the active rTMS or sham-stimulation groups. In the primary outcome, the decrease (least square [LS] mean ± standard error) in the weekly average of a pain diary at week 9 compared to the baseline was 0.84 ± 0.31 in the active rTMS group and 0.58 ± 0.29 in the sham group (LS mean difference, 0.26; 95% confidence interval, - 0.60 to 1.13). There was no significant effect on the interaction between the treatment group and time point. Pain-related disability score improved, but other assessments showed no differences. No serious adverse events were observed. This study did not show significant pain relief; however, active rTMS tended to provide better results than sham. rTMS has the potential to improve pain-related disability in addition to pain relief.Clinical Trial Registration number: jRCTs052190110 (20/02/2020).

Long latency electromyographic response induced by transcranial magnetic stimulation over the cerebellum preferentially appears during continuous visually guided manual tracking task.

We investigated whether long latency motor response induced by transcranial magnetic stimulation over the cerebellum (C-TMS) preferentially appears during a continuous visually guided manual tracking task, and whether it originates in a concomitantly evoked neck twitch. C-TMS or magnetic stimulation over the neck (N-MS) was delivered during one of four tasks: a continuous or discrete visually guided manual tracking task, or phasic or tonic contraction of the first dorsal interosseous muscle. The probability of long latency fluctuation of index finger movement induced by C-TMS was not significantly different from that induced by N-MS, but the probability of long latency fluctuation induced by C-TMS and that induced by N-MS was significantly higher than that induced by sham TMS during all the tasks. The probability of long latency electromyographic response in the first dorsal interosseous muscle induced by C-TMS was significantly higher than that induced by N-MS and that induced by sham TMS during the continuous visually guided manual tracking task. Such significant differences were not present during the other tasks. Long latency electromyographic response induced by C-TMS preferentially appears during the continuous visually guided manual tracking task and is not explained by a concomitantly evoked neck twitch.

The effect of eye movement on the control of arm movement to a target.

The purpose of this study was to investigate the effect of eye movement on the control of arm movement to a target. Healthy humans flexed the elbow to a stationary target in response to a start tone. Simultaneously, the subject moved the eyes to the target (saccade eye movement), visually tracked a laser point moving with the arm (smooth pursuit eye movement), or gazed at a stationary start point at the midline of the horizontal visual angle (non-eye movement--NEM). Arm movement onset was delayed when saccade eye movement accompanied it. The onset of an electromyographic burst in the biceps muscle and the onset of saccade eye movement were almost simultaneous when both the arm and the eyes moved to the target. Arm movement duration during smooth pursuit eye movement was significantly longer than that during saccade eye movement or NEM. In spite of these findings, amplitudes of motor-evoked potential in the biceps and triceps brachii muscles were not significantly different among the eye movement conditions. These findings indicate that eye movement certainly affects the temporal control of arm movement, but may not affect corticospinal excitability in the arm muscles during arm movement.

Effect of Posture during Trumpet and Marching Euphonium Performance on the Trunk and Lower Limb Musculoskeletal System.

[Purpose] The purpose of the present study was to investigate the effect of trumpet and marching euphonium performance posture on the trunk and lower limb musculoskeletal system. [Subjects] The subjects were 10 female university students. [Methods] Subjects maintained a resting position, a trumpet performance posture, and a marching euphonium performance posture. The angles and muscle activities of the trunk and lower limbs were then measured. [Results] The anterior tilt angle of the trunk decreased significantly in the trumpet and marching euphonium performance postures compared with the resting standing position, as well as in the marching euphonium performance posture compared with the trumpet performance posture. The muscle activity of the cervical paraspinal muscles, upper fibers of the trapezius, and lumbar paraspinal muscles increased significantly in the marching euphonium performance posture compared with the resting standing position, as well as in the marching euphonium performance posture compared with the trumpet performance posture. [Conclusion] The results suggest that the performance position for trumpet and the marching euphonium performance increases the load on the cervical and thoracic musculoskeletal system, which increases with greater instrument weight. However, the same instrument performance postures had no affect on the musculoskeletal system of the lower limbs.

Cerebellar TMS Induces Motor Responses Mediating Modulation of Spinal Excitability: A Literature Review.

Since individuals with cerebellar lesions often exhibit hypotonia, the cerebellum may contribute to the regulation of muscle tone and spinal motoneuron pool excitability. Neurophysiological methods using transcranial magnetic stimulation (TMS) of the cerebellum have been recently proposed for testing the role of the cerebellum in spinal excitability. Under specific conditions, single-pulse TMS administered to the cerebellar hemisphere or vermis elicits a long-latency motor response in the upper or lower limb muscles and facilitates the H-reflex of the soleus muscle, indicating increased excitability of the spinal motoneuron pool. This literature review examined the methods and mechanisms by which cerebellar TMS modulates spinal excitability.

Usefulness of the Cognitive Composition Test as an Early Discriminator of Mild Cognitive Impairment.

Mild cognitive impairment (MCI) is the preliminary stage of dementia, which is a serious social problem worldwide. This study aimed to investigate whether the Cognitive Composition Test (CCT) is effective for the early diagnosis of MCI. A total of 104 older adults underwent the Montreal Cognitive Assessment (MoCA), the Mini-Mental State Examination (MMSE), the Trail Making Test Parts A (TMT-A) and B (TMT-B), and our newly prototyped cognitive composition test (CCT). We created three types of CCT (CCT-A, CCT-B, and CCT-C) with different degrees of difficulty. First, we examined the concurrent validity of CCT-A, CCT-B, and CCT-C with the MoCA, MMSE, TMT-A, and TMT-B. All participants were classified into the healthy control (HC) and MCI groups based on their scores in the Japanese versions of the MoCA and MMSE. The HC and MCI groups were compared using the TMT-A, TMT-B, CCT-A, CCT-B, and CCT-C. Finally, we examined the sensitivity for discrimination of CCT-C. CCT-C had a higher discrimination sensitivity than TMT-A, TMT-B, CCT-A, and CCT-B, with a cut-off value of 65.75 s, a sensitivity level of 0.844, and a specificity of 0.776. It may be a useful screening tool for the early diagnosis of the early-stages of dementia, such as MCI, in asymptomatic older adults.

Effects of non-invasive brain stimulation for degenerative cerebellar ataxia: a protocol for a systematic review and meta-analysis.

INTRODUCTION: To date, the medical and rehabilitation needs of people with degenerative cerebellar ataxia (DCA) are not fully met because no curative treatment has yet been established. Movement disorders such as cerebellar ataxia and balance and gait disturbance are common symptoms of DCA. Recently, non-invasive brain stimulation (NIBS) techniques, including repetitive transcranial magnetic stimulation and transcranial electrical stimulation, have been reported as possible intervention methods to improve cerebellar ataxia. However, evidence of the effects of NIBS on cerebellar ataxia, gait ability, and activity of daily living is insufficient. This study will aim to systematically evaluate the clinical effects of NIBS on patients with DCA. METHODS AND ANALYSIS: We will conduct a preregistered systematic review and meta-analysis based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We will include randomised controlled trials to assess the effects of NIBS on patients with DCA. The primary clinical outcome will be cerebellar ataxia, as measured by the Scale for Assessment and Rating of Ataxia and the International Cooperative Ataxia Rating Scale. The secondary outcomes will include gait speed, functional ambulatory capacity and functional independence measure, as well as any other reported outcomes that the reviewer considers important. The following databases will be searched: PubMed, Cochrane Central Register of Controlled Trials, CINAHL and PEDro. We will assess the strength of the evidence included in the studies and estimate the effects of NIBS. ETHICS AND DISSEMINATION: Because of the nature of systematic reviews, no ethical issues are anticipated. This systematic review will provide evidence on the effects of NIBS in patients with DCA. The findings of this review are expected to contribute to clinical decision-making towards selecting NIBS techniques for treatment and generating new clinical questions to be addressed. PROSPERO REGISTRATION NUMBER: CRD42023379192.

Excessive excitability of inhibitory cortical circuit and disturbance of ballistic targeting movement in degenerative cerebellar ataxia.

This study aimed to investigate abnormalities in inhibitory cortical excitability and motor control during ballistic-targeting movements in individuals with degenerative cerebellar ataxia (DCA). Sixteen participants took part in the study (DCA group [n = 8] and healthy group [n = 8]). The resting motor-threshold and cortical silent period (cSP) were measured in the right-hand muscle using transcranial magnetic stimulation over the left primary motor cortex. Moreover, the performance of the ballistic-targeting task with right wrist movements was measured. The Scale for the Assessment and Rating of Ataxia was used to evaluate the severity of ataxia. The results indicated that the cSP was significantly longer in participants with DCA compared to that in healthy controls. However, there was no correlation between cSP and severity of ataxia. Furthermore, cSP was linked to the ballistic-targeting task performance in healthy participants but not in participants with DCA. These findings suggest that there is excessive activity in the gamma-aminobutyric acid-mediated cortical inhibitory circuit in individuals with DCA. However, this increase in inhibitory activity not only fails to contribute to the control of ballistic-targeting movement but also shows no correlation with the severity of ataxia. These imply that increased excitability in inhibitory cortical circuits in the DCA may not contribute the motor control as much as it does in healthy older adults under limitations associated with a small sample size. The study's results contribute to our understanding of motor control abnormalities in people with DCA and provide potential evidence for further research in this area.

The effect of advance information about the sequence of a to-be-signaled motor response on corticospinal excitability during the foreperiod.

We investigated the effect of advance information about the sequence of a to-be-signaled motor response on corticospinal excitability during the foreperiod in healthy humans. Advance information about the sequence of a to-be-signaled motor response was provided by a precue signal 600 ms before a response signal during a warned choice reaction task. The precue signal indicated the sequence of one of three to-be-signaled motor responses: simple, repetitive, or sequential motor responses. The amplitude of the motor-evoked potential (MEP) decreased significantly 100 ms before the response signal in both the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles, but a significant decrease was present only in the APB muscle 300 ms before the response signal. The decrease in the MEP amplitude 100 ms before the response signal induced by the precue signal indicating the repetitive motor response was significantly smaller than that induced by the precue signal indicating the simple or sequential motor response in the FDI muscle, and was significantly smaller than that induced by the precue signal indicating the sequential motor response in the APB muscle. The decrease in corticospinal excitability in the middle foreperiod is larger when the advance information about a to-be-signaled motor response is unrelated to the muscle tested, and the decrease in the late foreperiod is affected by advance information about the sequence of a to-be-signaled motor response.

Long latency fluctuation of the finger movement evoked by cerebellar TMS during visually guided manual tracking task.

The purpose of this study was to investigate whether right index finger movement during visually guided manual tracking task is fluctuated by transcranial magnetic stimulation (TMS) specifically over the cerebellum and is differently fluctuated by TMS over different sites of the cerebellum. TMS was delivered over the left, middle, or right cerebellum, or Pz. Index finger movement and electromyographic response in the first dorsal interosseous were recorded. Fluctuation of the finger movement appeared approximately 100 ms after cerebellar TMS with a probability of approximately 20%. The probability was significantly higher than that after TMS over the Pz or that after sham TMS. The probability was not significantly different among different TMS sites over the cerebellum. The long latency fluctuation of the finger movement during visually guided manual tracking task is evoked by TMS specifically over the cerebellum, but is not preferentially evoked by a specific site of the cerebellum. Cerebellar TMS induced long latency motor response may be useful to investigate the neural pathways activated by TMS over the cerebellum.