TMS brain mapping of the pharyngeal cortical representation in healthy subjects

BackgroundBrain mapping is fundamental to understanding brain organization and function. However, a major drawback to the traditional Brodmann parcellation technique is the reliance on the use of postmortem specimens. It has therefore historically been difficult to make any comparison regarding functional data from different regions or hemispheres within the same individual. Moreover, this method has been significant limited by subjective boundaries and classification criteria and therefore suffer from reproducibility issues. The development of transcranial magnetic stimulation (TMS) offers an alternative approach to brain mapping, specifically the motor cortical regions by eliciting quantifiable functional reactions.ObjectiveTo precisely describe the motor cortical topographic representation of pharyngeal constrictor musculature using TMS and to further map the brain for use as a tool to study brain plasticity.Methods51 healthy subjects (20 male/31 female, 19–26 years old) were tested using single-pulse TMS combined with intraluminal catheter-guided high-resolution manometry and a standardized grid cap. We investigated various parameters of the motor-evoked potential (MEP) that include the motor map area, amplitude, latency, center of gravity (CoG) and asymmetry index.ResultsCortically evoked response latencies were similar for the left and right hemispheres at 6.79 ± 0.22 and 7.24 ± 0.27 ms, respectively. The average scalp positions (relative to the vertex) of the pharyngeal motor cortical representation were 10.40 ± 0.19 (SE) cm medio-lateral and 3.20 ± 0.20 (SE) cm antero-posterior in the left hemisphere and 9.65 ± 0.24 (SE) cm medio-lateral and 3.18 ± 0.23 (SE) cm antero-posterior in the right hemisphere. The mean motor map area of the pharynx in the left and right hemispheres were 9.22 ± 0.85(SE) cm²and 10.12 ± 1.24(SE) cm², respectively. The amplitudes of the MEPs were 35.94 ± 1.81(SE)uV in the left hemisphere and 34.49 ± 1.95(SE)uV in the right hemisphere. By comparison, subtle but consistent differences in the degree of the bilateral hemispheric representation were also apparent both between and within individuals.ConclusionThe swallowing musculature has a bilateral motor cortical representation across individuals, but is largely asymmetric within single subjects. These results suggest that TMS mapping using a guided intra-pharyngeal EMG catheter combined with a standardized gridded cap might be a useful tool to localize brain function/dysfunction by linking brain activation to the corresponding physical reaction.     

Acute effects of spaced cathodal transcranial direct current stimulation in drug resistant focal epilepsies

ObjectiveTo evaluate the safety and temporal dynamic of the antiepileptic effect of spaced transcranial direct current stimulation (tDCS) in different focal epilepsies.MethodsCathodal tDCS with individual electrode placement was performed in 15 adults with drug resistant focal epilepsy. An amplitude of 2 mA was applied twice for 9 minutes, with an interstimulation interval of 20 minutes. Tolerability was assessed via the Comfort Rating Questionnaire and the frequency of interictal epileptiform discharges (IEDs) was sequentially compared between the 24 hours before and after tDCS.ResultsTDCS led to a significant reduction in the total number of IEDs/24 h by up to 68% (mean ± SD: −30.4 ± 21.1%, p = 0.001) as well as in seizure frequency (p = 0.041). The maximum IED reduction was observed between the 3rd and 21st hour after stimulation. Favorable clinical response was associated with structural etiology and clearly circumscribed epileptogenic foci but did not differ between frontal and temporal epilepsies. Overall, the tDCS treatment was well tolerated and did not lead to severe adverse events.ConclusionsThe spaced stimulation approach proved to be safe and well-tolerated in patients with drug-resistant unifocal epilepsies, leading to sustained IED and seizure frequency reduction.SignificanceSpaced tDCS induces mediate antiepileptic effects with promising therapeutic potential.     

Differentiating transcranial magnetic stimulation cortical and auditory responses via single pulse and paired pulse protocols: A TMS-EEG study

ObjectiveWe measured the neurophysiological responses of both active and sham transcranial magnetic stimulation (TMS) for both single pulse (SP) and paired pulse (PP; long interval cortical inhibition (LICI)) paradigms using TMS-EEG (electroencephalography).MethodsNineteen healthy subjects received active and sham (coil 90° tilted and touching the scalp) SP and PP TMS over the left dorsolateral prefrontal cortex (DLPFC). We measured excitability through SP TMS and inhibition (i.e., cortical inhibition (CI)) through PP TMS.ResultsCortical excitability indexed by area under the curve (AUC_(25-275ms)) was significantly higher in the active compared to sham stimulation (F(1,18) = 43.737, p < 0.001, η² = 0.708). Moreover, the amplitude of N100-P200 complex was significantly larger (F(1,18) = 9.118, p < 0.01, η² = 0.336) with active stimulation (10.38 ± 9.576 µV) compared to sham (4.295 ± 2.323 µV). Significant interaction effects were also observed between active and sham stimulation for both the SP and PP (i.e., LICI) cortical responses. Finally, only active stimulation (CI = 0.64 ± 0.23, p < 0.001) resulted in significant cortical inhibition.ConclusionThe significant differences between active and sham stimulation in both excitatory and inhibitory neurophysiological responses showed that active stimulation elicits responses from the cortex that are different from the non-specific effects of sham stimulation.SignificanceOur study reaffirms that TMS-EEG represents an effective tool to evaluate cortical neurophysiology with high fidelity.     

High-gamma modulation language mapping with stereo-EEG: A novel analytic approach and diagnostic validation

ObjectiveA novel analytic approach for task-related high-gamma modulation (HGM) in stereo-electroencephalography (SEEG) was developed and evaluated for language mapping.MethodsSEEG signals, acquired from drug-resistant epilepsy patients during a visual naming task, were analyzed to find clusters of 50–150 Hz power modulations in time–frequency domain. Classifier models to identify electrode contacts within the reference neuroanatomy and electrical stimulation mapping (ESM) speech/language sites were developed and validated.ResultsIn 21 patients (9 females), aged 4.8–21.2 years, SEEG HGM model predicted electrode locations within Neurosynth language parcels with high diagnostic odds ratio (DOR 10.9, p < 0.0001), high specificity (0.85), and fair sensitivity (0.66). Another SEEG HGM model classified ESM speech/language sites with significant DOR (5.0, p < 0.0001), high specificity (0.74), but insufficient sensitivity. Time to largest power change reliably localized electrodes within Neurosynth language parcels, while, time to center-of-mass power change identified ESM sites.ConclusionsSEEG HGM mapping can accurately localize neuroanatomic and ESM language sites.SignificancePredictive modelling incorporating time, frequency, and magnitude of power change is a useful methodology for task-related HGM, which offers insights into discrepancies between HGM language maps and neuroanatomy or ESM.     

A multimodal approach using TMS and EEG reveals neurophysiological changes in Parkinson's disease

IntroductionAlterations in large scale neural networks leading to neurophysiological changes have been described in Parkinson's disease (PD). The combination of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) has been suggested as a promising tool to identify and quantify neurophysiological mechanisms. The aim of this study was to investigate specific changes in electrical brain activity in response to stimulation of four brain areas in patients with PD.Methods21 healthy controls and 32 patients with PD underwent a combined TMS-EEG assessment that included stimulation of four brain areas: left M1, right M1, left dorso-lateral prefrontal cortex (DLPFC), and right DLPFC. Six measures were calculated to characterize the TMS evoked potentials (TEP) using EEG: (1) wave form adherence (WFA), (2) late phase deflection (LPD), (3) early phase deflection (EPD), (4) short-term plasticity (STP), (5) inter-trial adherence, and (6) connectivity between right and left M1 and DLPFC. A Linear mixed-model was used to compare these measures between groups and areas stimulated.ResultsPatients with PD showed lower WFA (p = 0.052), lower EPD (p = 0.009), lower inter-trial adherence (p < 0.001), and lower connectivity between homologs areas (p = 0.050), compared to healthy controls. LPD and STP measures were not different between the groups. In addition, lower inter-trial adherence correlated with longer disease duration (r = −0.355, p = 0.050).ConclusionsOur findings provide evidence to various alterations in neurophysiological measures in patients with PD. The higher cortical excitability along with increased variability and lower widespread of the evoked potentials in PD can elucidate different aspects related to the pathophysiology of the disease.     

Theta-burst versus 20 Hz repetitive transcranial magnetic stimulation in neuropathic pain: A head-to-head comparison

ObjectiveHigh-frequency repetitive transcranial magnetic stimulation (rTMS) has been shown to reduce neuropathic pain, but intermittent “theta-burst” stimulation (iTBS) could be a better alternative because of shorter duration and greater ability to induce cortical plasticity. Here we compared head-to-head the pain-relieving efficacy of the two modalities when applied daily for 5 days to patients with neuropathic pain.MethodsForty-six patients received 20 Hz-rTMS and/or iTBS protocols and 39 of them underwent the full two procedures in a random cross-over design. They rated pain intensity, sleep quality, fatigue and general health status daily during 5 consecutive weeks.ResultsPain relief during the month following stimulation was superior after 20 Hz-rTMS relative to iTBS (F(1,38) = 4.645; p = 0.037). Correlation between respective levels of maximal relief showed a significant deviation toward the 20 Hz-rTMS effect. A greater proportion of individuals responded to 20 Hz-rTMS (52% vs 32%, 95 %CI[0.095–3.27]; p = 0.06), and reports of fatigue significantly improved after 20 Hz-rTMS relative to iTBS (p = 0.01). General health and sleep quality scores did not differentiate both techniques.ConclusionsHigh-frequency rTMS appeared superior to iTBS for neuropathic pain relief.SignificanceAdequate matching between the oscillatory activity of motor cortex and that of rTMS may increase synaptic efficacy, thus enhancing functional connectivity of motor cortex with distant structures involved in pain regulation.     

Comparison of fiber tract low frequency stimulation to focal and ANT stimulation in an acute rat model of focal cortical seizures

BackgroundCurrent implementations of direct brain stimulation for epilepsy in patients involve high-frequency (HFS) electrical current and targeting of grey matter. Studies have shown that low-frequency (LFS) fiber-tract stimulation may also prove effective. To compare the efficacy of high-frequency grey matter stimulation to the low-frequency fiber tract stimulation technique a well-controlled set of experiments using a single animal model of epilepsy is needed.ObjectiveThe goal of this study was to determine the relative efficacy of different direct brain stimulation techniques for suppressing seizures using an acute rat model of focal cortical seizures.Methods4-AP was injected into the S1 region of cortex in rodents over 3 h. LFPs were recorded from the seizure focus and mirror focus to monitor seizure frequency during the experiments. CC-LFS, HFS-ANT, Focal-HFS, or a transection of the CC was applied.ResultsStimulation of the CC yielded a 65% ±14% (p = 0.0014) reduction of seizures in the focus and a 97% ±15% (p = 0.0026) reduction in the mirror focus (n = 7). By comparison transection of the CC produced a 65% ±18% reduction in the focus and a non-statistically significant reduction of 57% ±18% (p = 0.1381) in the mirror focus (n = 5). All other methods of stimulation failed to have a statistically significant effect on seizure suppression.ConclusionsLFS of the CC is the only method of stimulation to significantly reduce seizure frequency in this model of focal cortical seizures. These results support the hypothesis that LFSof fiber tracts has significant potential for seizure control.     

Long-term prophylactic efficacy of transcranial direct current stimulation in chronic migraine. A randomised,patient-assessor blinded,sham-controlled trial

ObjectiveTo assess the prophylactic effect of anodal tDCS of the left motor cortex in patients with resistant chronic migraine (CM) and its long-term maintenance.MethodsIn a patient-assessor blinded, sham-controlled trial, 36 patients were randomized to receive anodal tDCS (active group, n = 18) or sham tDCS (sham group, n = 18). The studied population was characterized by a previous failure of at least 3 classes of preventive drugs and a mean duration of migraine history of 26 years. The tDCS procedure consisted of an induction phase of 5 consecutive daily sessions (week 1) followed by a maintenance phase of 1 weekly session during the next 4 weeks and two bimonthly sessions in the next month, for a total of 11 sessions during 2 months. Anodal tDCS was delivered at 2 mA intensity for 20 min over the left motor cortex. The primary endpoint was the reduction in the monthly number of migraine attacks from baseline to each period of follow-up (months 1, 2, 3, 5) between the active and sham groups.ResultsThe monthly number of migraine attacks expressed as the percentage of reduction from baseline was significantly reduced in the active versus the sham group, from the end of first month (?21% ± 22 vs. ?2% ±25, p = 0.019) to the end of follow-up (3-month post-treatment) (?32% ± 33 vs. ?6% ±39, p = 0.011). At this time, the rate of responders, defined as a reduction of the monthly number of migraine attacks ≥30% from baseline, was significantly higher in the active group than in the sham group (50% vs. 14%, p = 0.043).ConclusionOur results show a marked prophylactic effect of anodal tDCS of the left motor cortex in resistant CM extending several months after the stimulation period, and suggest that this neuromodulatory approach may be part of the prophylactic alternatives available for CM.     

Assessment of safety of self-controlled repetitive trans-vertebral magnetic stimulation

ObjectiveThe aim of this study was to assess safety issues of self-controlled repetitive trans-vertebral magnetic stimulation (rTVMS) in humans.MethodsWe investigated effects of self-controlled rTVMS (≤20 Hz, ≤90% intensity) on vital signs and subjective sensations in 1690 trials of 30 healthy volunteers and 12 patients with spinal cord disorders.ResultsHealthy volunteers and the patients received 4595 ± 2345, and 4450 ± 2304 pulses in one day, respectively. No serious adverse events were observed in any participants, and only minor events were seen as follows. While blood pressure was unaffected in the patients, the diastolic blood pressure increased slightly after rTVMS in healthy volunteers. The peripheral capillary oxygen saturation increased after rTVMS in healthy volunteers. “Pain” or “Discomfort” was reported in approximately 10% of trials in both participants groups. Degree of the evoked sensation positively correlated with stimulus intensity and was affected by the site of stimulation.ConclusionSelf-controlled rTVMS (≤20 Hz and ≤90% intensity) did not induce any serious adverse effects in healthy volunteers and patients with spinal cord disorders.SignificanceOur results indicate that rTVMS can be used safely in physiological investigations in healthy volunteers and also as treatment for neurological disorders.     

Valproate but not levetiracetam slows the EEG alpha peak frequency – A pharmaco-EEG study

ObjectiveStudies of the effect of valproate (VPA) on the background EEG have shown varying results. Therefore, we compared the effect of VPA and levetiracetam (LEV) on the EEG alpha peak frequency (APF).MethodsWe retrospectively examined the APF in resting-state EEG of patients undergoing inpatient video-EEG monitoring (VEM) during withdrawal of VPA or LEV. We assessed APF trends by computing linear fits across individual patients’ APF as a function of consecutive days, and correlated the APF and daily antiseizure medication (ASM) doses on a single-patient and group level.ResultsThe APF in the VPA-group significantly increased over days with falling VPA doses (p = 0.005, n = 13), but did not change significantly in the LEV-group (p = 0.47, n = 18). APF correlated negatively with daily ASM doses in the VPA-group (average of r = −0.74 ± 0.12 across patients, p = 0.0039), but not in the LEV-group (average of r = −0.17 ± 0.18 across patients, p = 0.4072).ConclusionsOur results suggest that VPA treatment slows the APF. This APF reduction correlates with the daily dose of VPA and is not present in LEV treatment.SignificanceOur study identifies a VPA-related slowing of the APF even in patients without electroencephalographic or overt clinical signs of encephalopathy.     

Anodal transcranial direct current stimulation in chronic migraine and medication overuse headache: A pilot double-blind randomized sham-controlled trial

ObjectivesLittle evidence is available on the role of transcranial direct current stimulation (tDCS) in patients affected by chronic migraine (CM) and medication overuse headache (MOH). We aim to investigate the effects of tDCS in patients with CM and MOH as well as its role on brain activity.MethodsTwenty patients with CM and MOH were hospitalized for a 7-day detoxification treatment. Upon admission, patients were randomly assigned to anodal tDCS or sham stimulation delivered over the primary motor cortex contralateral to the prevalent migraine pain side every day for 5 days. Clinical data were recorded at baseline (T0), after 1 month (T2) and 6 months (T3). EEG recording was performed at T0, at the end of the tDCS/Sham treatment, and at T2.ResultsAt T2 and T3, we found a significant reduction in monthly migraine days (p = 0.001), which were more pronounced in the tDCS group when compared to the sham group (p = 0.016).At T2, we found a significant increase of alpha rhythm in occipital leads, which was significantly higher in tDCS group when compared to sham group.ConclusionstDCS showed adjuvant effects to detoxification in the management of patients with CM and MOH. The EEG recording showed a significant potentiation of alpha rhythm, which may represent a correlate of the underlying changes in cortico-thalamic connections.SignificanceThis study suggests a possible role for tDCS in the treatment of CM and MOH. The observed clinical improvement is coupled with a potentiation of EEG alpha rhythm.     

Postoperative navigated transcranial magnetic stimulation to predict motor recovery after surgery of tumors in motor eloquent areas

ObjectiveTo know whether motor deficits after tumor surgery are transient is reassuring for the patient and crucial for planning rehabilitation and adjuvant treatment. We analyze the value of postoperative MRI navigated transcranial magnetic stimulation (nTMS) compared to intraoperative MEP monitoring in predicting recovery of motor function.MethodsRetrospective series of nTMS mappings within 14 days after surgery for supratentorial tumors (09/2014–05/2018). All patients with motor deficits of Medical-Research-Council-Grade (MRCS) 0–4- were included.ResultsWe performed nTMS mapping on average 3.8 days after surgery and recorded nTMS MEP in 11 of 13 patients. Motor strength recovered to at least MRCS 4 within one month if postoperative nTMS elicited MEPs (positive predictive value 90.9%). If nTMS did not elicit MEPs, the patient did not recover (negative predictive value 100%). Intraoperative MEP and postoperative nTMS were equally predictive for long-term motor recovery. In cases of intraoperative MEP alteration/signal loss, but a positive postoperative nTMS mapping, 2/3 patients demonstrated a good motor recovery.ConclusionnTMS may predict long-term motor recovery of patients suffering from severe motor deficits directly after resection of tumors located in motor eloquent areas.SignificanceIn cases of intraoperative MEP alterations, postoperative nTMS may clarify the potential for motor recovery.     

Could non-HDL-cholesterol be a better marker of atherogenic dyslipidemia in obstructive sleep apnea?

Background/objectiveObstructive sleep apnea (OSA) is independently associated with dyslipidemia, a surrogate marker of atherosclerosis. Low-density lipoprotein (LDL)-cholesterol is accepted as a major independent risk factor for cardiovascular disease. However, non-high-density lipoprotein (HDL)-cholesterol is a better marker of atherogenic dyslipidemia and recommended as a target of lipid lowering therapy. We aimed to assess the prevalence of atherogenic dyslipidemia, and relationship between OSA severity and serum LDL-cholesterol and non-HDL cholesterol levels in OSA patients.MethodsWe retrospectively evaluated treatment naïve 2361 subjects admitted to the sleep laboratory of a university hospital for polysomnography. All subjects’ lipid profile including total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and non-HDL-cholesterol were measured.ResultsOut of 2361 patients (mean age 49.6 ± 11.9 years; 68.9% male, apnea-hypopnea index 36.6 ± 28.4/h), 185 (7.8%) had no OSA and 2176 (92.2%) had OSA. Atherogenic dyslipidemia prevalence was high (57–66%) in OSA patients, and especially increased in severe OSA compared to other groups (p < 0.05). Though total and LDL-cholesterol did not differ between those with and without OSA, non-HDL-cholesterol (p = 0.020), and triglycerides (p = 0.001) were higher and HDL-cholesterol levels (p = 0.018) were lower in OSA patients than non-OSA. Non-HDL-cholesterol was significantly correlated with OSA severity (p < 0.001) and hypoxia parameters (p < 0.01), whereas LDL-cholesterol showed no correlation.ConclusionsAtherogenic dyslipidemia is highly prevalent and non-HDL-cholesterol levels are significantly increased, predominantly in severe OSA patients. Non-HDL-cholesterol but not LDL-cholesterol, is significantly correlated with OSA severity and hypoxia parameters. Therefore, it could be better to use non-HDL-cholesterol, which is a guideline recommended target of lipid therapy, as a marker of atherosclerotic cardiovascular risk in OSA patients.     

Dissociating the causal role of left and right dorsal premotor cortices in planning and executing bimanual movements – A neuro-navigated rTMS study

BackgroundThe dorsal premotor cortex (PMd) is a key region in bimanual coordination. However, causal evidence linking PMd functionality during motor planning and execution to movement quality is lacking.ObjectiveWe investigated how left (PMd_L) and right PMd (PMd_R) are causally involved in planning and executing bimanual movements, using short-train repetitive transcranial magnetic stimulation (rTMS). Additionally, we explored to what extent the observed rTMS-induced modulation of performance could be explained by rTMS-induced modulation of PMd-M1 interhemispheric interactions (IHI).MethodsTwenty healthy adults (mean age ± SD = 22.85 ± 3.73 years) participated in two sessions, in which either PMd_L or PMd_R was targeted with rTMS (10 Hz) in a pseudo-randomized design. PMd functionality was transiently modulated during the planning or execution of a complex bimanual task, whereby the participant was asked to track a moving dot by controlling two dials. The effect of rTMS on several performance measures was investigated. Concurrently, rTMS-induced modulation of PMd-M1 IHI was measured using a dual-coil paradigm, and associated with the rTMS-induced performance modulation.ResultsrTMS over PMd_L during planning increased bilateral hand movement speed (p = 0.03), thereby improving movement accuracy (p = 0.02). In contrast, rTMS over PMd_R during both planning and execution induced deterioration of movement stability (p = 0.04). rTMS-induced modulation of PMd-M1 IHI during planning did not predict rTMS-induced performance modulation.ConclusionThe current findings support the growing evidence on PMd_L dominance during motor planning, as PMd_L was crucially involved in planning the speed of each hand, subserving bimanual coordination accuracy. Moreover, the current results suggest that PMd_R fulfills a role in continuous adjustment processes of movement.     

The relationship between gross motor function impairment in cerebral palsy and sleeping issues of children and caregivers

AimTo investigate, among children and adolescents with cerebral palsy (CP), the relationship between impairment of the gross motor function and: (i) child sleep disorders; (ii) the need for nocturnal support; and (iii) the quality of sleep of their caregivers.MethodsFor children, we considered their scores on the gross motor function measure (GMFM-88) and on the sleep disturbance scale for children (SDSC), besides analyzing qualitative features about their sleep. For caregivers, we considered their scores in the Pittsburgh sleep quality index (PSQI).ResultsOur sample was comprised of 87 participants with mean age of 11.4 years old (±3.4). We observed correlations between GMFM-88 and disorders of initiating and maintaining sleep (DIMS) (r = −0.22; p = 0.039), sleep–wake transition disorders (SWTD) (r = 0.26; p = 0.017) and disorders of arousal (DA) (r = 0.23; p = 0.033). Children receiving nocturnal support presented lower scores in the GMFM-88 (p = 0.001) and higher scores in the SDSC (p = 0.029). For the caregivers, we found no correlation between GMFM-88 and PSQI. Nonetheless, their PSQI scores correlated with the SDSC scores (r = 0.24; p = 0.027).ConclusionImpairment of the gross motor function correlated with DIMS and the need for nocturnal support but might not have an impact on the caregivers’ sleep, which in turn correlated with child sleep disorders.     

Objective measurement of limb bradykinesia using a marker-less tracking algorithm with 2D-video in PD patients

BackgroundQuantitative measurement of parkinsonian motor symptoms is crucial in clinical practice and in research. However, the widely used Unified PD Rating Scale (UPDRS) part III is based on a semi-quantitative evaluation with high inter- and intra-rater variability. Sensor-based measurements have been widely studied but are limited for their accessibility.MethodsWe analyzed 2D-RGB videos recording finger tapping and leg agility tests in 29 PD patients with a marker-less deep-learning based tracking algorithm. The tracking performance was validated with an accelerometer. Four parameters (mean amplitude, mean interpeak interval, amplitude variability and interpeak interval variability) were calculated from the position tracking.ResultsThe performance of the video-tracking was in good agreement with the accelerometer-based tracking (Intra-class correlation coefficient > 0.9 for the peak amplitude, and >0.6 for the interpeak interval). The video-tracking successfully captured variable aspects of limb bradykinesia that have a distinct correlation with the general parkinsonian motor symptoms and gait. In the finger-tapping task, the mean amplitude (R = −0.6, p = 2.4 × 10⁻⁶), amplitude variability (R = 0.36, p = 0.0092), mean interpeak interval (R = 0.34, p = 0.014), and interpeak interval variability (R = 0.66, p = 1.4 × 10⁻⁷) was significantly correlated with the UPDRS scores. In leg agility test, the mean amplitude (R = −0.58, p = 1.7 × 10⁻⁵), mean interpeak interval (R = 0.37, p = 0.0088) and interpeak interval variability (R = 0.7, p = 6.2 × 10⁻⁸) were significantly correlated with the UPDRS scores, but not with amplitude variability (R = 0.17, p = 0.26). Limb rigidity was significantly correlated with the interpeak interval (R = 0.40, p = 0.0036) and its variability (R = 0.59, p = 4.2 × 10⁻⁶) in the leg agility test.ConclusionThe video-based tracking could objectively measure limb bradykinesia in PD patients.     

Monitoring of patients with brainstem hemorrhage: A simultaneous study of quantitative electroencephalography and transcranial Doppler

ObjectiveTo explore whether quantitative electroencephalography (QEEG) and transcranial Doppler (TCD) can be used to evaluate patients with acute severe brainstem hemorrhage (ASBH).MethodsWe prospectively enrolled patients with ASBH and assessed their mortality at the 90-day follow-up. The patients' demographic data, serological data, and clinical factors were recorded. Quantitative brain function monitoring was performed using a TCD-QEEG recording system attached to the patient’s bedside.ResultsThirty-one patients (55.3 ± 10.6 years; 17 men) were studied. Mortality at 90 days was at 61.3%. There was no significant difference in TCD-related parameters between the survival group and the death group (p > 0.05). Among the QEEG-related indexes, only the (delta + theta)/(alpha + beta) ratio (DTABR) (odds ratio 11.555, 95%confidence interval 1.413–94.503, p = 0.022) was an independent predictor of clinical outcome; the area under the ROC curve of DTABR was 0.921, cut-off point was 3.88, sensitivity was 79%, and specificity was 100%.ConclusionsIn patients with ASBH, QEEG can effectively inform the clinical prognosis regarding 90-day mortality, while TCD cannot.SignificanceQEEG shows promise for informing the mortality prognosis of patients with ASBH.     

Contribution of altered corticospinal microstructure to gait impairment in children with cerebral palsy

ObjectiveCorticospinal tract (CST) injury may lead to motor disorders in children with Cerebral Palsy (CP). However, the precise underlying mechanisms are still ambiguous. We aimed to characterize the CST structure and function in children with CP and determine their contributions to balance and gait impairments.MethodTwenty-six children with spastic CP participated. Transcranial magnetic stimulation (TMS) and diffusion tensor imaging (DTI) were utilized to characterize CST structure and function. Common clinical measures were used to assess gait speed, endurance and balance, and mobility.ResultsCST structure and function were significantly altered in children with CP. Different abnormal patterns of CST structure were identified as either abnormal appearance of brain hemispheres (Group-1) or semi-normal CST appearance (Group-2). We found significant correlations between the DTI parameters of the more affected CST and gait features only in Group-1.ConclusionCST structure and function are abnormal in children with CP and these abnormalities may contribute to balance and gait impairment in some children with CP.SignificanceOur findings may lead to the development of further investigations on the mechanisms underlying gait impairment in children with CP and on decision-making for more effective rehabilitation.     

Sleep-disordered breathing in cystic fibrosis

IntroductionCystic fibrosis (CF) is a life-shortening, genetic disease that affects approximately 30,000 Americans. Although patients frequently report snoring, mouth breathing, and insomnia, the extent to which sleep-disordered breathing (SDB) may underlie these complaints remains unknown.MethodsSingle-center retrospective review of polysomnography results from referred patients with and without CF individually-matched (1:2) for age, gender, race, and body mass index (BMI).ResultsMean ages were 8.0 ± 5.2 (sd) and 35.9 ± 12.9 years, among 29 children and 23 adults with CF respectively. The CF and non-CF groups were well-matched in age and BMI. Subjects with vs. without CF had three times greater odds of moderate-severe SDB (apnea-hypopnea index (AHI) ≥ 5 in children, ≥ 15 in adults) (p = 0.01). Nocturnal oxygen saturation nadir (Minimum SpO₂) was lower among CF vs. non-CF groups (p = 0.002). For every 1-unit increase in AHI, the decline in Minimum SpO₂ was larger for subjects with vs. without CF (p = 0.05). In subjects with CF, forced expiratory volume in 1 s percent predicted (FEV1 PPD) was associated with Minimum SpO₂ (Pearson r = 0.68, p < 0.0001) but not AHI (r = −0.19, p = 0.27). For every 1-unit increase in AHI, magnitude of decline in Minimum SpO₂ was larger for those with low vs. normal FEV1 PPD (p = 0.01).ConclusionSeverity of SDB may be worse among referred patients with vs. without CF. The SDB may modify the relationship between CF lung disease and nocturnal hypoxemia. Markers of lung disease severity including lung function do not predict SDB severity, suggesting the need for routine polysomnography to screen for this sleep disorder.     

Influence of post-stroke fatigue on reaction times and corticospinal excitability during movement preparation

ObjectivesReduced corticospinal excitability at rest is associated with post-stroke fatigue (PSF). However, it is not known if corticospinal excitability prior to a movement is also altered in fatigue which may then influence subsequent behaviour. We hypothesized that the levels of PSF can be explained by differences in modulation of corticospinal excitability during movement preparation.Methods73 stroke survivors performed an auditory reaction time task. Corticospinal excitability was measured using transcranial magnetic stimulation. Fatigue was quantified using the fatigue severity scale. The effect of time and fatigue on corticospinal excitability and reaction time was analysed using a mixed effects model.ResultsThose with greater levels of PSF showed reduced suppression of corticospinal excitability during movement preparation and increased facilitation immediately prior to movement onset (β = −0.0066, t = −2.22, p = 0.0263). Greater the fatigue, slower the reaction times the closer the stimulation time to movement onset (β = 0.0024, t = 2.47, p = 0.0159).ConclusionsLack of pre-movement modulation of corticospinal excitability in high fatigue may indicate poor sensory processing supporting the sensory attenuation model of fatigue.SignificanceWe take a systems-based approach and investigate the motor system and its role in pathological fatigue allowing us to move towards gaining a mechanistic understanding of chronic pathological fatigue.