TMS-evoked N100 responses as a prognostic factor in acute stroke.

Rehabilitation programs, to be efficiently tailored, need clear prognostic markers. In acute stroke, neurophysiological measures, such as motor evoked potentials (MEPs), have been proposed, although with discordant results. The aim of this study was to identify a reliable neurophysiological measure of recovery in acute post-stroke individuals by combining MEPs and the N100 component of transcranial magnetic stimulation-evoked potentials (TEPs). Nine acute post-stroke subjects were included. Clinical evaluation performed in the first week after the event included administration of the European Stroke Scale and Barthel Index and recording of MEPs and TEPs; administration of the clinical scales was repeated after one and three months. The presence/absence of MEPs and TEPs showed correlations with motor outcome. Individuals with a poorer outcome showed absence of both MEPs and TEPs; absence of MEPs alone was related to a partial recovery. Given the results of this exploratory study, further investigation is needed to define the accuracy of combined use of MEPs and TEPs as an approach for predicting motor recovery after acute stroke.

Paroxysmal dysarthria-ataxia in remitting-relapsing Bickerstaff's-like encephalitis.

Paroxysmal dysarthria-ataxia is a rare neurological condition due to ephaptic transmission, generally appearing in multiple sclerosis patients characterized by stereotyped attacks of slurred speech usually accompanied by ataxia, appearing many times a day. Here we describe a patient with an unusual remitting-relapsing form of Bickerstaff's-like brainstem encephalitis who manifested PDA after a relapse with the involvement of a peculiar region below the red nuclei and benefited from lamotrigine.

Transcranial direct current stimulation (tDCS) for sleep disturbances and fatigue in patients with post-polio syndrome.

PURPOSE: Post-polio syndrome develops about 20-40 years after acute paralytic poliomyelitis, and manifests with progressively deteriorating muscle strength and endurance. Here, we assessed whether transcranial direct current stimulation (tDCS) improves sleep and fatigue symptoms in patients with post-polio syndrome. METHODS: We enrolled 32 patients with a diagnosis of post-polio syndrome. tDCS (1.5 mA, 15 min) was delivered by a direct current stimulator connected to three electrodes: two anodal electrodes on the scalp over the right and left pre-motor cortex and the other above the left shoulder (cathode). 16 patients received anodal tDCS and the remainder sham tDCS. We evaluated changes induced by tDCS (daily for five days a week, for three weeks) on clinical scales (Short Form Health Survey [SF-36], Piper Fatigue Scale [PFS], Fatigue Severity Scale [FSS], 101-Point Numerical Rating [PNR-101], Hamilton Rating Scale for Depression [HRSD], Pittsburgh Sleep Quality Index [PSQI]) at baseline (T0) and three weeks later (T1). RESULTS: At T1 SF-36 sub-items physical functioning, role physical, vitality, social functioning and role emotional improved significantly more in patients who received tDCS (p < 0.01) than in sham-treated patients. Also, PSQI scores improved more in treated patients (p < 0.05, two-way ANOVA with "stimulation" and "time" as factors: p < 0.01). tDCS-induced benefits were more pronounced in patients who were younger at primary infection (p < 0.05). CONCLUSION: Anodal tDCS over the pre-motor areas for fifteen days improved sleep and fatigue symptoms in patients with post-polio syndrome. tDCS could be a non-invasive and valuable new tool for managing post-polio patients.

Effects of prefrontal repetitive transcranial magnetic stimulation on the autonomic regulation of cardiovascular function.

Several protocols based on repetitive transcranial magnetic stimulation (rTMS) have been proposed for treatment of a variety of neurological disorders. Despite the widespread use, little is known about the effects of rTMS on the autonomic nervous control of the cardiovascular system. Twelve volunteers underwent rTMS sessions consisted in 8-min baseline recording, 8-min 0.7-Hz rTMS stimulation at 100 % of the motor cortex excitability threshold on the prefrontal cortex of one randomly assigned hemisphere. After 8-min recovery, the same procedure was performed on the contra-lateral hemisphere. Non-invasive (Portapres device) beat-by-beat blood pressure and heart period time series were recorded and analyzed by spectral and cross-spectral analysis in the low-frequency (LF ≈ 0.1 Hz) and in the high-frequency (HF = respiratory frequency) range. Repetitive TMS, particularly after stimulation of the right hemisphere, induced a slight increase in the parasympathetic drive and no effects on the sympathetic activity. There was a significant bradycardia after stimulation on the right hemisphere, not significant bradycardia after left stimulation. LF/HF ratio was 3.8 ± 2.1 during baseline and changed to 1.9 ± 0.6 during rTMS on the left and to 1.6 ± 0.6 during rTMS on the right. No significant changes were observed in blood pressure. Low-frequency rTMS of the prefrontal cortex induces a slight parasympathetic activation and no changes in the sympathetic function.

Risk factors for post-polio syndrome among an Italian population: a case-control study.

Post-polio syndrome (PPS) is a clinical syndrome of new weakness, fatigue and musculoskeletal pain occurring in a variable proportion of polio survivors decades after acute disease. To date, several risk factors for PPS development have been reported, although the etiology of this disorder remains elusive. Using a case-control design, we aimed to assess risk indicators for PPS in a group of Italian polio survivors. Subjects with prior poliomyelitis attending the rehabilitation hospital of Malcesine, Italy, were the target population. Patients with PPS, diagnosed according to the European Federation of Neurological Societies criteria, served as cases, while patients not meeting diagnostic criteria for PPS were used as controls. All subjects were assessed through a structured questionnaire made of 82 questions and neurological examination. The association with investigated risk factors (sex, age at polio onset, age at onset of symptoms, extension and severity of polio, employment) was analyzed by the calculation of the odds ratio. A total of 161 out of 391 eligible patients met the adopted diagnostic criteria for PPS, giving a frequency of 41.2%. Symptoms most frequently complained by PPS patients were loss of muscle strength, loss of resistance, loss of muscle volume and generalized fatigue. Female gender, the presence of respiratory disturbance during the acute phase of polio and the use of orthoses and aids during the recovery and stabilization represented independent risk factors for PPS in the studied population.

Inherited demyelinating neuropathies with micromutations of peripheral myelin protein 22 gene.

The peripheral myelin protein 22 gene (PMP22) encodes an intrinsic membrane protein of compact myelin. Duplication or deletion of PMP22 causes the most common autosomal dominant neuropathies, Charcot-Marie-Tooth disease type 1A or hereditary neuropathy with liability to pressure palsies. Charcot-Marie-Tooth disease type 1A is a hypertrophic de-remyelinating neuropathy manifesting with peroneal muscular atrophy and uniform, marked, slowing of nerve conduction velocities. Hereditary neuropathy with liability to pressure palsies is a recurrent focal neuropathy with sausage-like myelin thickening (tomacula) and non-uniform nerve conduction velocity changes. Missense or nonsense mutations also cause more severe Charcot-Marie-Tooth disease type 1A forms of infancy or hereditary neuropathy with liability to pressure palsies, but they are presumably very rare. We performed a mutational scanning of PMP22 in 229 index patients (46 familial, 183 isolated) referred for suspected inherited neuropathy. The series included 125 cases with hereditary neuropathy with liability to pressure palsies (mean age 42.5 years), 47 cases with Charcot-Marie-Tooth disease type 1A (motor nerve conduction velocities at median nerve below 38 m/s) (mean age 40.7 years) and 57 cases with Charcot-Marie-Tooth with unknown nerve conduction velocities (mean age 43 years). Preliminary molecular studies ruled out PMP22 duplication or deletion or mutations in a comprehensive panel of Charcot-Marie-Tooth genes. Mutational scanning of PMP22 was done by denaturing high performance liquid chromatography and automated nucleotide sequencing. To investigate the molecular basis of phenotype-to-genotype correlations, we performed a transcriptional analysis of PMP22 using reverse-transcriptase polymerase chain reaction and quantitative real-time polymerase chain reaction in two phenotypically divergent nerve biopsies. Ten patients harboured eight micromutations of PMP22 including four novel changes. In six familial and three sporadic cases, detected mutations caused premature or delayed stop codons and were associated with hereditary neuropathy with liability to pressure palsies; the related pathological pictures ranged from classical tomaculous neuropathy to a mild demyelinating neuropathy with atypical non-tomaculous myelin thickenings. In a single family a c.179-2A> G mutation affecting the splice acceptor site of intron 2 cosegregated with a Charcot-Marie-Tooth disease type 1A-like syndrome and a peculiar pathological picture of demyelinating neuropathy without Charcot-Marie-Tooth disease type 1A-like classical onion bulbs or tomacula. Transcriptional analysis of a novel c.174_178 + 7delAAACGGTGAGGC deletion involving exon 2 and intron 2 demonstrated an unstable mutant transcript leading to a p.Asn59GlyfsX12 change; the mutation represented a null allele and caused a typical tomaculous hereditary neuropathy with liability to pressure palsies. The Charcot-Marie-Tooth disease type 1-like c.179-2A > G allele led to a stable transcript with an in-frame deletion of exon 3 (p.Glu60_Ala106del); the predicted shorter protein could exert variable molecular effects. In conclusion, micromutations of PMP22 cause a clinical and pathological continuum of demyelinating neuropathies that may include atypical phenotypes.

Efficacy of botulinum toxin type A treatment of functional impairment of degenerative hip joint: Preliminary results.

OBJECTIVE: The aim of this study was to investigate the effect of botulinum toxin type A injection into the adductor muscles in reducing pain and improving joint mobility and quality of life in patients affected by hip osteoarthritis. METHODS: A total of 39 outpatients, mean age 68 years (age range 41-82 years), were evaluated using the Harris Hip Score to test hip function, a visual analogue scale to measure pain intensity and the Short Form 36 (SF-36) questionnaire to assess patient well-being and quality of life at baseline, 2, 4 and 12 weeks after treatment with botulinum toxin type A. A total of 400 U of botulinum toxin type A (Dysport) was injected into the adductor longus muscle and the adductor magnus muscle. RESULTS: The Harris Hip Score increased significantly after 2, 4 and 12 weeks (df 3, chi2 = 45.1; p < 0.0001). A significant decrease in pain intensity was detected at all the follow-up visits, after 2, 4 and 12 weeks (df 3; chi2 = 27.8; p < 0.001). The SF-36 score was significantly higher 4 and 12 weeks after treatment. At each evaluation visit a significant correlation was detected between decreased pain and improved hip mobility. CONCLUSION: Botulinum toxin type A induced a reduction in pain, indicating that this might be an innovative, less invasive treatment in patients affected by severe hip osteoarthritis, with remarkable effects on the clinical management of this disease.

Changes in cerebral activity after decreased upper-limb hypertonus: an EMG-fMRI study.

OBJECTIVE: Whereas several studies have used functional magnetic resonance imaging (fMRI) to investigate motor recovery, whether therapy to decrease post-stroke hypertonus alters central motor patterns remains unclear. In this study, we used continuous electromyography (EMG)-fMRI to investigate possible changes in movement-related brain activation in patients receiving Botulinum toxin (BoNT-A) for hand-muscle hypertonus after chronic stroke. METHODS: We studied eight stroke patients all of whom had hemiparesis and associated upper-limb hypertonus. All patients underwent an fMRI-EMG recording and clinical-neurological assessment before BoNT-A and 5 weeks thereafter. The handgrip motor task during imaging was fixed across both patients and controls. The movements were metronome paced, movement amplitude and force were controlled with a plastic orthosis, dynamometer and EMG recording. An age-matched control group was recruited from among healthy volunteers underwent the same fMRI-EMG recording. RESULTS: Before BoNT-A, while patients moved the paretic hand, fMRI detected wide bilateral activation in the sensorymotor areas (SM1), in the supplementary motor area (SMA) and cerebellum. After BoNT-A blood oxygenation level-dependent (BOLD) activation decreased in ipsilateral and contralateral motor areas and became more lateralized. BOLD activation decreased also in ipsilateral cerebellar regions and in the SMA. CONCLUSION: Changes in peripheral upper-limb hypertonus after BoNT-A were associated to an improvement in active movements and more lateralized and focalized activation of motor areas. The clinical and EMG-fMRI coregistration technique we used to study hand-muscle hypertonus in patients receiving BoNT-A after chronic stroke should be useful in future studies seeking improved strategies for post-stroke neurorehabilitation.

Steady-state activation in somatosensory cortex after changes in stimulus rate during median nerve stimulation.

Passive electrical stimulation activates various human somatosensory cortical systems including the contralateral primary somatosensory area (SI), bilateral secondary somatosensory area (SII) and bilateral insula. The effect of stimulation frequency on blood oxygenation level-dependent (BOLD) activity remains unclear. We acquired 3-T functional magnetic resonance imaging (fMRI) in eight healthy volunteers during electrical median nerve stimulation at frequencies of 1, 3 and 10 Hz. During stimulation BOLD signal changes showed activation in the contralateral SI, bilateral SII and bilateral insula. Results of fMRI analysis showed that these areas were progressively active with the increase of rate of stimulation. As a major finding, the contralateral SI showed an increase of peak of BOLD activation from 1 to 3 Hz but reached a plateau during 10-Hz stimulation. Our finding is of interest for basic research and for clinical applications in subjects unable to perform cognitive tasks in the fMRI scanner.

A double blind placebo RCT to investigate the effects of serotonergic modulation on brain excitability and motor recovery in stroke patients.

Motor excitability is increased in both hemispheres in stroke patients during motor recovery. Pharmacologically controlled changes of cortical excitability might be beneficial for synaptic plasticity and therefore facilitate functional recovery after a brain lesion. In particular, it has been suggested that antidepressant drugs can modulate motor excitability. Several recent reports suggest the possibility of monitoring pharmacological effects on brain excitability through transcranial magnetic stimulation (TMS). The aim of this study was to investigate motor area excitability in patients with stroke after oral administration of citalopram. We conducted a prospective randomised placebo controlled study. Twenty patients with unilateral stroke were included in the study: ten patients treated by antidepressive drug and ten patients with placebo. A selective serotonergic drug (citalopram) or a placebo was administered using a mean dosage of 10 mg/day in combination with physiotherapy. Motor cortex excitability was studied by single and paired transcranial magnetic stimulation. TMS recording was tested before (T1) and 1 month after (T2) beginning drug treatment. Patients treated by the serotonergic drug, compared to patients that received a placebo, showed a significant improvement in neurological status as measured by NIHSS and a decrease of motor excitability over the unaffected hemisphere, while no differences were observed over the affected hemisphere. Our findings suggest that treatment with serotonergic drugs can bring about a significant decrease of the motor cortex excitability in stroke patients with effects on both the affected and unaffected hemispheres associated with a better motor recovery.

EEG and FMRI coregistration to investigate the cortical oscillatory activities during finger movement.

Electroencephalography combined with functional magnetic resonance imaging (EEG-fMRI) may be used to identify blood oxygenation level dependent (BOLD) signal changes associated with physiological and pathological EEG event. In this study we used EEG-fMRI to determine the possible correlation between topographical movement-related EEG changes in brain oscillatory activity recorded from EEG electrodes over the scalp and fMRI-BOLD cortical responses in motor areas during finger movement. Thirty-two channels of EEG were recorded in 9 subjects during eyes-open condition inside a 1.5 T magnetic resonance (MR) scanner using a MR-compatible EEG recording system. Off-line MRI artifact subtraction software was applied to obtain continuous EEG data during fMRI acquisition. For EEG data analysis we used the event-related-synchronization/desynchronization (ERS/ERD) approach to investigate where movement-related decreases in alpha and beta power are located. For image statistical analysis we used a general linear model (GLM) approach. There was a significant correlation between the positive-negative ratio of BOLD signal peaks and ERD values in the electrodes over the region of activation. We conclude that combined EEG-fMRI may be used to investigate movement-related oscillations of the human brain inside an MRI scanner and the movement-related changes in the EMG or EEG signals are useful to identify the brain activation sources responsible for BOLD-signal changes.

Expression of gangliosides on glial and neuronal cells in normal and pathological adult human brain.

Few studies have assessed the glycolipid phenotype of glial cells in the human central nervous system (CNS) in situ. We investigated by immunohistochemistry the expression and cellular distribution of a panel of gangliosides (GM1, GM2, acetyl-GM3, GD1a, GD1b, GD2, GD3, GT1b, GQ1b and the A2B5 antibody) in adult, human normal and pathological brain, namely multiple sclerosis (MS) and other neurological diseases (OND). In normal conditions, we found diffuse expression in the white matter of most gangliosides tested, with the exception of acetyl-GM3, GT1b and GQ1b. By double immunofluorescence with phenotypic markers, GM1 and GD1b were preferentially expressed on GFAP+ astrocytes, GD1a on NG2+ oligodendrocyte precursors, A2B5 immunostained both populations, while GD2 was selectively present on mature oligodendrocytes. In the gray matter, only GM1, GD2 and A2B5 were present on neuronal cells. Interestingly, those gangliosides present on astrocytes in normal conditions were preferentially expressed on NG2+ cells in chronic MS lesions and in OND. Selective expression of GT1b upon astrocytes and NG2+ cells was instead observed in MS lesions, but not in OND. The definition of the glycolipid phenotype of CNS glial cells may be useful to identify distinct biological glial subsets and provide insights on the potential autoantigenic role of gangliosides in CNS autoimmune diseases.