Altered motor cortex physiology and dysexecutive syndrome in patients with fatigue and cognitive difficulties after mild COVID-19.

BACKGROUND AND PURPOSE: Fatigue and cognitive difficulties are reported as the most frequently persistent symptoms in patients after mild SARS-CoV-2 infection. An extensive neurophysiological and neuropsychological assessment of such patients was performed focusing on motor cortex physiology and executive cognitive functions. METHODS: Sixty-seven patients complaining of fatigue and/or cognitive difficulties after resolution of mild SARS-CoV-2 infection were enrolled together with 22 healthy controls (HCs). Persistent clinical symptoms were investigated by means of a 16-item questionnaire. Fatigue, exertion, cognitive difficulties, mood and 'well-being' were evaluated through self-administered tools. Utilizing transcranial magnetic stimulation of the primary motor cortex (M1) resting motor threshold, motor evoked potential amplitude, cortical silent period duration, short-interval intracortical inhibition, intracortical facilitation, long-interval intracortical inhibition and short-latency afferent inhibition were evaluated. Global cognition and executive functions were assessed with screening tests. Attention was measured with computerized tasks. RESULTS: Post COVID-19 patients reported a mean of 4.9 persistent symptoms, high levels of fatigue, exertion, cognitive difficulties, low levels of well-being and reduced mental well-being. Compared to HCs, patients presented higher resting motor thresholds, lower motor evoked potential amplitudes and longer cortical silent periods, concurring with reduced M1 excitability. Long-interval intracortical inhibition and short-latency afferent inhibition were also impaired, indicating altered GABAB -ergic and cholinergic neurotransmission. Short-interval intracortical inhibition and intracortical facilitation were not affected. Patients also showed poorer global cognition and executive functions compared to HCs and a clear impairment in sustained and executive attention. CONCLUSIONS: Patients with fatigue and cognitive difficulties following mild COVID-19 present altered excitability and neurotransmission within M1 and deficits in executive functions and attention.

European Academy of Neurology and European Federation of Neurorehabilitation Societies guideline on pharmacological support in early motor rehabilitation after acute ischaemic stroke.

BACKGROUND AND PURPOSE: Early pharmacological support for post-stroke neurorehabilitation has seen an abundance of mixed results from clinical trials, leaving practitioners at a loss regarding the best options to improve patient outcomes. The objective of this evidence-based guideline is to support clinical decision-making of healthcare professionals involved in the recovery of stroke survivors. METHODS: This guideline was developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework. PubMed, Cochrane Library and Embase were searched (from database inception to June 2018, inclusive) to identify studies on pharmacological interventions for stroke rehabilitation initiated in the first 7 days (inclusive) after stroke, which were delivered together with neurorehabilitation. A sensitivity analysis was conducted on identified interventions to address results from breaking studies (from end of search to February 2020). RESULTS: Upon manually screening 17,969 unique database entries (of 57,001 original query results), interventions underwent meta-analysis. Cerebrolysin (30 ml/day, intravenous, minimum 10 days) and citalopram (20 mg/day, oral) are recommended for clinical use for early neurorehabilitation after acute ischaemic stroke. The remaining interventions identified by our systematic search are not recommended for clinical use: amphetamine (5, 10 mg/day, oral), citalopram (10 mg/day, oral), dextroamphetamine (10 mg/day, oral), Di-Huang-Yi-Zhi (2 × 18 g/day, oral), fluoxetine (20 mg/day, oral), lithium (2 × 300 mg/day, oral), MLC601(3 × 400 mg/day, oral), phosphodiesterase-5 inhibitor PF-03049423 (6 mg/day, oral). No recommendation 'for' or 'against' is provided for selegiline (5 mg/day, oral). Issues with safety and tolerability were identified for amphetamine, dextroamphetamine, fluoxetine and lithium. CONCLUSIONS: This guideline provides information for clinicians regarding existing pharmacological support in interventions for neurorecovery after acute ischaemic stroke. Updates to this material will potentially elucidate existing conundrums, improve current recommendations, and hopefully expand therapeutic options for stroke survivors.

Effects of Intermittent Theta Burst Stimulation on the Clock Drawing Test Performances in Patients with Alzheimer's Disease.

The clock drawing test (CDT) is widely used in clinical neuropsychological practice. However, its neuroanatomical correlates have not been well established. This study investigated the effects of theta burst stimulation (TBS) applied over different brain regions on CDT scores in patients with Alzheimer's disease (AD). The 10-20 positions F3, F4, T3, T4, TP3, TP4, P3, P4, as determined by a 10-20 positioning cap, were targeted. Excitatory intermittent TBS (iTBS) was given over the above-mentioned eight regions to ten AD patients and ten control subjects on separate days. CDT was administered at baseline (T0), during the 5 min following the TBS (T1) and 60 min after TBS (T2), with an inter-session interval of at least 4 days. iTBS over TP4 and P4 transiently increased Rouleau CDT score in AD patients. When targeting TP4 and P4, mainly the area of the supramarginal/angular gyrus and the inferior parietal lobe, corresponding respectively to the Brodmann areas 40/39 and 7/40, are reached. iTBS thus seems able to modulate activity of the right posterior parietal cortex in AD patients performing the CDT. Our results provide physiological evidence that those parietal regions are functionally important for the execution of the Rouleau CDT. This finding suggests that CDT has reliable neuroanatomical correlates, and support the notion that this test can be used as a good marker of right parietal brain dysfunction. The present study also highlights the therapeutic potential of the induction of neuromodulatory effects using non-invasive brain stimulation techniques.

Effects of intrathecal baclofen therapy in subjects with disorders of consciousness: a reappraisal.

Baclofen is a structural analogue of gamma-amino-butyric acid (GABA), which reduces spastic hypertonia of striated muscle due to a mechanism of GABAB-ergic inhibition of mono- and polysynaptic reflexes at the spinal level. There are reports of patients with severe disorders of consciousness that presented a substantial improvement following intrathecal baclofen (ITB) administration for severe spasticity. The neural mechanisms underlying the clinical recovery after ITB have not yet been clarified. Baclofen could modulate sleep-wake cycles that may be dysregulated and thus interfere with alertness and awareness. The diminished proprioceptive and nociceptive sensory inputs may relieve thalamo-cortical neural networks involved in maintaining the consciousness of the self and the world. ITB treatment might also promote the recovery of an impaired GABAergic cortical tone, restoring the balance between excitatory and inhibitory cortical activity. Furthermore, glutamatergic synapses are directly or indirectly modulated by GABAB-ergic receptors. Neurophysiological techniques (such as transcranial magnetic stimulation, electroencephalography, or the combination of both) can be helpful to explore the effects of intrathecal or oral baclofen on the modulation of neural cortical circuits in humans with disorders of consciousness.

Modulation of exteroceptive electromyographic responses in defensive peripersonal space.

The cutaneous silent period (CSP) to noxious finger stimulation constitutes a robust spinal inhibitory reflex that protects the hand from injury. In certain conditions, spinal inhibition is interrupted by a brief burst-like electromyographic activity, dividing the CSP into two inhibitory phases (I1 and I2). This excitatory component is termed long-loop reflex (LLR) and is presumed to be transcortical in origin. Efficient defense from environmental threats requires sensorimotor integration between multimodal sensory afferents and planning of defensive movements. In the defensive peripersonal space (DPPS) immediately surrounding the body, we interact with objects and persons with increased alertness. We investigated whether CSP differs when the stimulated hand is in the DPPS of the face compared with a distant position. Furthermore, we investigated the possible role of vision in CSP modulation. Fifteen healthy volunteers underwent CSP testing with the handheld either within 5 cm from the nose (near) or away from the body (far). Recordings were obtained from first dorsal interosseous muscle following index (D2) or little finger (D5) stimulation with varying intensities. A subgroup of subjects underwent CSP recordings in near and far conditions, both with eyes open and with eyes closed. No inhibitory CSP parameter differed between stimulation in near and far conditions. LLRs occurring following D2 stimulation were significantly larger in near than far conditions at all stimulus intensities, irrespective of subjects seeing their hand. Similar to the hand-blink reflex, spinally organized protective reflexes may be modulated by corticospinal facilitatory input when the hand enters the DPPS of the face. NEW & NOTEWORTHY The present findings demonstrate for the first time that a spinally organized protective reflex, the cutaneous silent period (CSP), may be modulated by top-down corticospinal facilitatory input when the stimulated hand enters the defensive peripersonal space (DPPS) of the face. In particular, the cortically mediated excitatory long-loop reflex, which may interrupt the CSP, is facilitated when the stimulated hand is in the DPPS, irrespective of visual control over the hand. No spinal inhibitory CSP parameter differs significantly in or outside the DPPS.

Cholinergic transmission is impaired in patients with idiopathic normal-pressure hydrocephalus: a TMS study.

The pathophysiological mechanisms of cognitive and gait disturbances in subjects with normal-pressure hydrocephalus (NPH) are still unclear. Cholinergic and other neurotransmitter abnormalities have been reported in animal models of NPH. The objective of this study was to evaluate the short latency afferent inhibition (SAI), a transcranial magnetic stimulation protocol which gives the possibility to test an inhibitory cholinergic circuit in the human brain, in subjects with idiopathic NPH (iNPH). We applied SAI technique in twenty iNPH patients before ventricular shunt surgery. Besides SAI, also the resting motor threshold and the short intracortical inhibition to paired stimulation were assessed. A significant reduction of the SAI (p = 0.016), associated with a less pronounced decrease of the resting motor threshold and the short latency intracortical inhibition to paired stimulation, were observed in patients with iNPH at baseline evaluation. We also found significant (p < 0.001) correlations between SAI values and the gait function tests, as well as between SAI and the neuropsychological tests. These findings suggest that the impairment of cholinergic neurons markedly contributes to cognitive decline and gait impairment in subjects with iNPH.

Intrathecal Baclofen Trial Before Device Implantation: 12-Year Experience With Continuous Administration.

OBJECTIVE: To report our experience using continuous intrathecal baclofen (ITB) administration prior to a possible ITB device implantation. DESIGN: Retrospective open label study. Mean duration of follow-up 64 months. SETTING: Primary-care and referral center, ambulatory and hospitalized care. PARTICIPANTS: Patients (N=116) undergoing continuous ITB trials between 2006 and 2017. INTERVENTIONS: Continuous application of baclofen via a temporary intrathecal catheter connected to an external pump. MAIN OUTCOME MEASURES: Assessment of the modified Ashworth Scale and range of movement prior versus end of ITB trial. According to the Barthel Index, definition of high-level patients (60-100 scoring points) and low-level patients (0-55 scoring points). Calculation of the Rivermead Mobility Index in high-level patients prior versus end of ITB trial. Evaluation of occurring adverse events. RESULTS: A total of 119 ITB trials were performed in 116 patients (78 men, mean age 41±16), 113 patients completed the trials (31 of 113 high level, 82 of 113 low level). The median modified Ashworth scale improved from 4 (interquartile range [IQR] 3-4) to 2 (IQR 1-2; P≤.001), the range of movement from 2 (IQR 1-3) to 3 (IQR 3-3; P≤.001). The Rivermead Mobility Index increased from 9 (IQR 6-12) to 10 (IQR 7-12.5; P=.004) in high-level patients. Eighty-eight out of 113 patients (78%) were appropriate candidates for ITB device surgery, 75 of 88 (85%) proceeded to an implantation. A total of 69 adverse events occurred in 57 of 119 trials (48%), 37 of 69 (54%) were drug related, 32 of 69 (46%) were procedure related, and 42 of 69 (61%) were minor. The ITB device was implanted in 69 of 75 patients (92%) at last follow-up. CONCLUSIONS: Continuous administration of ITB is an effective and useful alternative to ITB bolus application during ITB screening period. Half of the patients experienced adverse events; the majority were minor events.

Effect of Intrathecal Baclofen on Pain and Quality of Life in Poststroke Spasticity.

Background and Purpose- Intrathecal baclofen (ITB) is an effective treatment for managing patients with severe poststroke spasticity, who can experience continued pain and decline in their quality of life (QoL). SISTERS (Spasticity In Stroke-Randomized Study) was a randomized, controlled, open-label, multicenter, phase 4 study to evaluate ITB therapy versus conventional medical management (CMM) with oral antispastic medications for treatment of poststroke spasticity. Methods- Poststroke patients with spasticity in ≥2 extremities and an Ashworth Scale score of ≥3 in ≥2 affected lower extremity muscle groups were randomized (1:1) to ITB (N=31) or CMM (N=29). Both treatment arms received physiotherapy throughout. The primary outcome was the change in average Ashworth Scale score in the lower extremities of the affected side from baseline to month 6. Here, we report results for secondary outcomes: pain via the Numeric Pain Rating Scale, health-related QoL by the EuroQol-5 dimensional 3 level utility score and health status visual analog scale score, stroke-specific QoL, and patient satisfaction. Analyses were performed on an intention-to-treat basis. Results- We observed significant treatment effects in favor of ITB over CMM for changes from baseline to month 6 in Numeric Pain Rating Scale scores for actual pain (ITB versus CMM: mean, -1.17 [SD, 3.17] versus 0.00 [3.29]; median, -1.00 versus 0.00; P=0.0380) and least pain (mean, -1.61 [2.29] versus 0.24 [3.07]; median, -1.00 versus 0.00; P=0.0136), and EuroQol-5 dimensional 3 level utility scores (mean, +0.09 [0.26] versus +0.01 [0.16]; median, +0.07 versus 0.00; P=0.0197). Between-group differences were not statistically significant for EuroQol-5 dimensional 3 level visual analog scale, stroke-specific QoL summary, or Numeric Pain Rating Scale worst pain scores, although ITB patients showed greater numeric improvements from baseline during follow-up. More ITB patients than CMM patients (73% versus 48%) were satisfied with the spasticity reduction at month 6. Conclusions- These data support that ITB therapy is associated with improvements in pain and QoL in poststroke patients. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT01032239.

Intrathecal baclofen therapy versus conventional medical management for severe poststroke spasticity: results from a multicentre, randomised, controlled, open-label trial (SISTERS).

BACKGROUND: Intrathecal baclofen (ITB) is a treatment option for patients with severe poststroke spasticity (PSS) who have not reached their therapy goal with other interventions. METHODS: 'Spasticity In Stroke-Randomised Study' (SISTERS) was a randomised, controlled, open-label, multicentre phase IV study to evaluate the efficacy and safety of ITB therapy versus conventional medical management (CMM) with oral antispastic medications for treatment of PSS. Patients with chronic stroke with spasticity in ≥2 extremities and an Ashworth Scale (AS) score ≥3 in at least two affected muscle groups in the lower extremities (LE) were randomised (1:1) to ITB or CMM. Both treatment arms received physiotherapy throughout. The primary outcome was the change in the average AS score in the LE of the affected body side from baseline to month 6. Analyses were performed for all patients as randomised (primary analysis) and all randomised patients as treated (safety analysis). RESULTS: Of 60 patients randomised to ITB (n=31) or CMM (n=29), 48 patients (24 per arm) completed the study. The primary analysis showed a significant effect of ITB therapy over CMM (mean AS score reduction, -0.99 (ITB) vs -0.43 (CMM); Hodges-Lehmann estimate, -0.667(95.1%CI -1.0000 to -0.1667); P=0.0140). More patients reported adverse events while receiving ITB (24/25 patients, 96%; 149 events) compared with CMM (22/35, 63%; 77 events), although events were generally consistent with the known safety profile of ITB therapy. CONCLUSIONS: These data support the use of ITB therapy as an alternative to CMM for treatment of generalised PSS in adults. TRIAL REGISTRATION NUMBER: NCT01032239; Results.

Quantification of Upper Limb Motor Recovery and EEG Power Changes after Robot-Assisted Bilateral Arm Training in Chronic Stroke Patients: A Prospective Pilot Study.

Background: Bilateral arm training (BAT) has shown promise in expediting progress toward upper limb recovery in chronic stroke patients, but its neural correlates are poorly understood. Objective: To evaluate changes in upper limb function and EEG power after a robot-assisted BAT in chronic stroke patients. Methods: In a within-subject design, seven right-handed chronic stroke patients with upper limb paresis received 21 sessions (3 days/week) of the robot-assisted BAT. The outcomes were changes in score on the upper limb section of the Fugl-Meyer assessment (FM), Motricity Index (MI), and Modified Ashworth Scale (MAS) evaluated at the baseline (T0), posttraining (T1), and 1-month follow-up (T2). Event-related desynchronization/synchronization were calculated in the upper alpha and the beta frequency ranges. Results: Significant improvement in all outcomes was measured over the course of the study. Changes in FM were significant at T2, and in MAS at T1 and T2. After training, desynchronization on the ipsilesional sensorimotor areas increased during passive and active movement, as compared with T0. Conclusions: A repetitive robotic-assisted BAT program may improve upper limb motor function and reduce spasticity in the chronically impaired paretic arm. Effects on spasticity were associated with EEG changes over the ipsilesional sensorimotor network.

Prognostic Importance of Lesion Location on Functional Outcome in Patients with Cerebellar Ischemic Stroke: a Prospective Pilot Study.

To date, few studies focused on prediction of functional recovery after cerebellar stroke. The main aim of this prospective pilot study was to determine the association between cerebellar lesion location and functional outcome in adults with acute cerebellar infarction. We examined 14 patients with first-ever unilateral cerebellar ischemic stroke within 7 days and at 90 days from the onset of stroke by means of the International Cooperative Ataxia Rating Scale. Cerebellar lesions were traced from magnetic resonance imaging performed within 72 h since stroke and region of interest were generated. The association between the International Cooperative Ataxia Rating Scale score and lesion location was determined with the voxel-based lesion-symptom mapping methods implemented in the MRIcro software. Colored lesion-symptom maps representing the z statistics were generated and overlaid onto the MNI-ICBM 152 linear probabilistic atlas of the human brain and the Johns Hopkins University white matter templates. Our results documented that injuries to the V, VI, VIIA Crus I, VIIA Crus II, VIIB, VIIIA, and VIIIB lobules and the middle cerebellar peduncle are significantly associated with the International Cooperative Ataxia Rating Scale (ICARS) score at 1 week after the onset of stroke. Furthermore, we found that injuries to the VI, VIIA Crus I, VIIA Crus II, VIIB, VIIIA, and VIIIB lobules, the dentate nucleus, and the middle cerebellar peduncle are significantly associated with the ICARS score at 3 months since the cerebellar stroke onset. The findings of this pilot study might improve prognostic accuracy of functional outcome in patients with acute cerebellar infarction.

Cortical afferent inhibition abnormalities reveal cholinergic dysfunction in Parkinson's disease: a reappraisal.

Parkinson's disease (PD) is a multisystem neurodegenerative disorder affecting, besides the dopaminergic function, multiple neurotransmission systems, including the cholinergic system. Central cholinergic circuits of human brain can be tested non-invasively by coupling peripheral nerve stimulation with transcranial magnetic stimulation (TMS) of motor cortex; this test is named short latency afferent inhibition (SAI). SAI abnormalities have been reported in PD patients with gait disturbances and many non-motor symptoms, such as visual hallucinations (VHs), REM sleep behavior disorder (RBD), dysphagia, and olfactory impairment. The findings of these TMS studies strongly suggest that cholinergic degeneration is an important contributor to a number of clinical features of PD. TMS and neuropsychological raise the possibility that the presence of RBD, VHs and olfactory dysfunction indicate increased risk of cognitive impairment in patients with PD. Longitudinal studies of the patients are required to verify whether SAI abnormalities can predict a future severe cognitive decline. TMS can provide simple measures that may represent suitable biomarkers of cholinergic neurotransmission in PD. SAI studies enable an early recognition of PD patients with cholinergic system degeneration, and this might allow future targeted cholinergic treatment approaches, in addition to dopaminergic therapy, to ameliorate non-motor and motor clinical symptoms in PD patients.

Reduced TMS-evoked EEG oscillatory activity in cortical motor regions in patients with post-COVID fatigue.

OBJECTIVE: Persistent fatigue is a major symptom of the so-called 'long-COVID syndrome', but the pathophysiological processes that cause it remain unclear. We hypothesized that fatigue after COVID-19 would be associated with altered cortical activity in premotor and motor regions. METHODS: We used transcranial magnetic stimulation combined with EEG (TMS-EEG) to explore the neural oscillatory activity of the left primary motor area (l-M1) and supplementary motor area (SMA) in a group of sixteen post-COVID patients complaining of lingering fatigue as compared to a sample of age-matched healthy controls. Perceived fatigue was assessed with the Fatigue Severity Scale (FSS) and Fatigue Rating Scale (FRS). RESULTS: Post-COVID patients showed a remarkable reduction of beta frequency in both areas. Correlation analysis exploring linear relation between neurophysiological and clinical measures revealed a significant inverse correlation between the individual level of beta oscillations evoked by TMS of SMA with the individual scores in the FRS (r(15) = -0.596; p = 0.012). CONCLUSIONS: Post-COVID fatigue is associated with a reduction of TMS-evoked beta oscillatory activity in SMA. SIGNIFICANCE: TMS-EEG could be used to identify early alterations of cortical oscillatory activity that could be related to the COVID impact in central fatigue.

Lowered Delta Activity in Post-COVID-19 Patients with Fatigue and Cognitive Impairment.

In post-COVID-19 syndrome (PCS), neurocognitive symptoms and fatigue are often associated with alterations in electroencephalographic (EEG) activity. The present study investigates the brain source activity at rest in PCS patients (PCS-pts) perceiving cognitive deficits and fatigue. A total of 18 PCS-pts and 18 healthy controls (HCs) were enrolled. A Montreal Cognitive Assessment (MoCA), Perceived Cognitive Difficulties Scale (PDCS) and Fatigue Severity Scale (FSS) were administered for assessing the symptoms' severity. Brain activity at rest, both with open (OE) and closed eyes (CE), was recorded by high-density EEG (Hd-EEG) and localized by source estimation. Compared to HCs, PCS-pts exhibited worse performance in executive functions, language and memory, and reported higher levels of fatigue. At resting OE state, PCS-pts showed lower delta source activity over brain regions known to be associated with executive processes, and these changes were negatively associated with PDCS scores. Consistent with recent literature data, our findings could indicate a dysfunction in the neuronal networks involved in executive functions in PCS-pts complaining of fatigue and cognitive impairment.

Conscious agency vs. pre-conscious sensory filtering: Disparate suppression of trigeminal blink reflex by self-stimulation and by prepulses.

Modulation of the blink reflex (BR) to supraorbital nerve (SON) stimulation by a weak somatosensory prepulse (sPP) consists of inhibition of R2 and facilitation of R1. Similar BR changes occur with self-stimulation. Our aim was to compare neurophysiological processes underlying both effects. We assessed BR parameters in 18 healthy participants following right SON stimulation either performed by an experimenter (experiment 1A) or following self-stimulation (experiments 1B, 1C). In experiments 1A and 1C, sPPs to digit 2 preceded SON stimuli by 40, 100, 200 and 500 ms. In experiment 1B: self-stimulation was delayed by 40, 100, 200, and 500 ms. In experiment 2, BRs were elicited by an experimenter randomly during a 2-s period before participants applied self-stimulation. In experiment 1, as expected, sPPs caused facilitation of R1 and inhibition of R2, which peaked at 100 ms ISI, similarly in experiments 1A and 1C. Self-stimulation caused a decrease of R2, which was evident in a broad range of time intervals. In experiment 2, R2 was already inhibited at the onset of the 2-s period, while R1 began to rise significantly 1.4 s before self-stimulation. Both effects progressively increased until self-triggering. The results concur with a time-locked gating mechanism of prepulses at brainstem level, whereas self-stimulation modulates BR in a tonic manner, reflecting a cognitive influence due to self-agency.

Co-ultramicronized palmitoylethanolamide/luteolin normalizes GABAB-ergic activity and cortical plasticity in long COVID-19 syndrome.

OBJECTIVE: Transcranial magnetic stimulation (TMS) studies showed that patients with cognitive dysfunction and fatigue after COVID-19 exhibit impaired cortical GABAB-ergic activity, as revealed by reduced long-interval intracortical inhibition (LICI). Aim of this study was to test the effects of co-ultramicronized palmitoylethanolamide/luteolin (PEA-LUT), an endocannabinoid-like mediator able to enhance GABA-ergic transmission and to reduce neuroinflammation, on LICI. METHODS: Thirty-nine patients (26 females, mean age 49.9 ± 11.4 years, mean time from infection 296.7 ± 112.3 days) suffering from persistent cognitive difficulties and fatigue after mild COVID-19 were randomly assigned to receive either PEA-LUT 700 mg + 70 mg or PLACEBO, administered orally bid for eight weeks. The day before (PRE) and at the end of the treatment (POST), they underwent TMS protocols to assess LICI. We further evaluate short-latency afferent inhibition (SAI) and long-term potentiation (LTP)-like cortical plasticity. RESULTS: Patients treated with PEA-LUT but not with PLACEBO showed a significant increase of LICI and LTP-like cortical plasticity. SAI remained unaffected. CONCLUSIONS: Eight weeks of treatment with PEA-LUT restore GABAB activity and cortical plasticity in long Covid patients. SIGNIFICANCE: This study confirms altered physiology of the motor cortex in long COVID-19 syndrome and indicates PEA-LUT as a candidate for the treatment of this post-viral condition.

Pregabalin: a treatment option for dystonia?

To date, no studies are available on the effect of pregabalin in dystonia. A patient with subarachnoidal and cerebral hemorrhage was treated with pregabalin for neuropathic pain. Upon withdrawal of the medication she experienced spontaneous and painful supination in the right foot and internal hip rotation when standing up. When pregabalin was reinstituted, these dystonic symptoms subsided, but reappeared when the medication was again discontinued. One possible explanation for these symptoms could be neuronal hyperactivity within still-functioning pathways in connection with the motor cortex. Preponderance of activity in potentially compensatory structures could be suppressed by pregabalin: therefore, its potential benefit in subacute secondary dystonia in cases with orbital brain involvement is suggested.

Quantification of clinical scores through physiological recordings in low-responsive patients: a feasibility study.

Clinical scores represent the gold standard in characterizing the clinical condition of patients in vegetative or minimally conscious state. However, they suffer from problems of sensitivity, specificity, subjectivity and inter-rater reliability.In this feasibility study, objective measures including physiological and neurophysiological signals are used to quantify the clinical state of 13 low-responsive patients. A linear regression method was applied in nine patients to obtain fixed regression coefficients for the description of the clinical state. The statistical model was extended and evaluated with four patients of another hospital. A linear mixed models approach was introduced to handle the challenges of data sets obtained from different locations.Using linear backward regression 12 variables were sufficient to explain 74.4% of the variability in the change of the clinical scores. Variables based on event-related potentials and electrocardiogram account for most of the variability.These preliminary results are promising considering that this is the first attempt to describe the clinical state of low-responsive patients in such a global and quantitative way. This new model could complement the clinical scores based on objective measurements in order to increase diagnostic reliability. Nevertheless, more patients are necessary to prove the conclusions of a statistical model with 12 variables.

TMS for the functional evaluation of cannabis effects and for treatment of cannabis addiction: A review.

The knowledge about the effects of cannabis on human cortical brain processes is increasing. In this regard, transcranial magnetic stimulation (TMS) enables the evaluation of central nervous system function, including drug effects. Moreover, repetitive TMS (rTMS) has been used therapeutically in several substance use disorders. In this scoping review, we summarize and discuss studies that have employed TMS and rTMS techniques in users of cannabis for recreational purposes. In subjects with a history of persistent cannabis use, TMS studies showed reduced short-interval cortical inhibition (SICI). This observation points more at neurobiological changes of chronic cannabis use than to a direct effect of cannabis on gamma-aminobutyric acid (GABA) A receptors. Moreover, individuals vulnerable to becoming long-term users of cannabis may also have underlying pre-existing abnormalities in SICI. Of note, the use of cannabis is associated with an increased risk of schizophrenia, and the down-regulation of GABAergic function may play a role. Less frequent cannabis use and spontaneous craving were observed following rTMS applied to the dorsolateral prefrontal cortex (DLPFC). There is emerging evidence that the posterior cingulate cortex and the precuneus are potential targets for rTMS intervention in cannabis use disorder. However, larger and randomized trials should corroborate these encouraging findings.