Rehabilitation Modulates High-Order Interactions Among Large-Scale Brain Networks in Subacute Stroke.

The recovery of motor functions after stroke is fostered by the functional integration of large-scale brain networks, including the motor network (MN) and high-order cognitive controls networks, such as the default mode (DMN) and executive control (ECN) networks. In this paper, electroencephalography signals are used to investigate interactions among these three resting state networks (RSNs) in subacute stroke patients after motor rehabilitation. A novel metric, the O-information rate (OIR), is used to quantify the balance between redundancy and synergy in the complex high-order interactions among RSNs, as well as its causal decomposition to identify the direction of information flow. The paper also employs conditional spectral Granger causality to assess pairwise directed functional connectivity between RSNs. After rehabilitation, a synergy increase among these RSNs is found, especially driven by MN. From the pairwise description, a reduced directed functional connectivity towards MN is enhanced after treatment. Besides, inter-network connectivity changes are associated with motor recovery, for which the mediation role of ECN seems to play a relevant role, both from pairwise and high-order interactions perspective.

Motor and Cognitive Modulation of a Single Session of Transcutaneous Auricular Vagus Nerve Stimulation in Post Stroke Patients: A Pilot Study.

Objective: The aim of the present study is to explore whether a single session of transcutaneous Vagus Nerve Stimulation (tVNS) can enhance the ipsilesional, and contralesional upper limb motor functions as well as cognitive functions in stroke patients. The effects of the stimulation were evaluated through two different tasks: the box and blocks test (BB), indexing manual dexterity, and the Go/No-go task, a visuomotor paradigm used to assess both motor readiness and response inhibition. Tests were administered without tVNS, during tVNS and during sham tVNS. Results: The BB showed a statistical difference for both contralesional side (p = 0.05) between Basal-Real condition (p = 0.042) and ipsilesional side (p = 0.001) between Basal-Real (p = 0.008) and for Real-Sham (p = 0.005). Any statistical difference was found for the mean latencies in the three conditions of the Go/No-go test. Conclusion: A single session of tVNS seems to improve upper limb motor functions but not cognitive functions in post-stroke patients, despite a positive trend was detected.

Comparison between directed causal flow metrics for the assessment of resting-state EEG motor network connectivity in subacute stroke patients.

Isolated effective coherence (iCoh) is a measure of neural causal functional connectivity from EEG signals that was proven to overperform the Generalized Partial Directed Coherence (gPDC). However, iCoh sensitivity in the identification of reliable functional neural connections with respect to random links was not investigated. This study aims to compare the sensitivity of iCoh and gPDC with a statistical surrogates' approach. The cerebral motor network topology of a cohort of subjects in sub-acute stage after stroke was investigated. iCoh showed enhanced statistical discriminative power of the relevant connections within the motor network with respect to gPDC. This property influenced the assessment of ipsilesional intra-hemispheric topographic variations occurring in the population after a physical rehabilitation program.

Upper-limb actuated exoskeleton for muscular dystrophy patients: preliminary results.

Being able to perform a lost movement is an important experience towards increased independence and self-esteem, particularly for neuromuscular patients, who see their muscles weaken day after day. In this pilot study, preliminary results on the testing of a motorized upper-limb exoskeleton for muscular dystrophy patients are presented. The mechatronic system is a five Degrees of Freedom exoskeleton, which acts at shoulder, elbow, and wrist levels. It is designed to help severely impaired people to regain independence during daily-life activities. While wearing the exoskeleton, the user has the direct control of the system by actively piloting the position of end-effector by means of joystick or vocal control. The usability of the system and a quantitative assessment of arm functionality with and without the exoskeleton are evaluated on five muscular dystrophy patients. According to the objective functional benefit evaluation performed through the PUL scale, all participants strongly increased their range of motion and they were able to perform activities that were not possible without the exoskeleton, such as such as feeding, playing activities at the table, combing hair or using a keyboard. As for the evaluation of self-perceived functional benefit, four patients reflected the effective measured functional improvement. System usability has been evaluated to be good.

The combined action of a passive exoskeleton and an EMG-controlled neuroprosthesis for upper limb stroke rehabilitation: First results of the RETRAINER project.

The combined use of Functional Electrical Stimulation (FES) and robotic technologies is advocated to improve rehabilitation outcomes after stroke. This work describes an arm rehabilitation system developed within the European project RETRAINER. The system consists of a passive 4-degrees-of-freedom exoskeleton equipped with springs to provide gravity compensation and electromagnetic brakes to hold target positions. FES is integrated in the system to provide additional support to the most impaired muscles. FES is triggered based on the volitional EMG signal of the same stimulated muscle; in order to encourage the active involvement of the patient the volitional EMG is also monitored throughout the task execution and based on it a happy or sad emoji is visualized at the end of each task. The control interface control of the system provides a GUI and multiple software tools to organize rehabilitation exercises and monitor rehabilitation progress. The functionality and the usability of the system was evaluated on four stroke patients. All patients were able to use the system and judged positively its wearability and the provided support. They were able to trigger the stimulation based on their residual muscle activity and provided different levels of active involvement in the exercise, in agreement with their level of impairment. A randomized controlled trial aimed at evaluating the effectiveness of the RETRAINER system to improve arm function after stroke is currently ongoing.

Effect of human-robot interaction on muscular synergies on healthy people and post-stroke chronic patients.

Robot-assisted training is a widely used technique to promote motor re-learning on post-stroke patients that suffer from motor impairment. While it is commonly accepted that robot-based therapies are potentially helpful, strong insights about their efficacy are still lacking. The motor re-learning process may act on muscular synergies, which are groups of co-activating muscles that, being controlled as a synergic group, allow simplifying the problem of motor control. In fact, by coordinating a reduced amount of neural signals, complex motor patterns can be elicited. This paper aims at analyzing the effects of robot assistance during 3D-reaching movements in the framework of muscular synergies. 5 healthy people and 3 neurological patients performed free and robot-assisted reaching movements at 2 different speeds (slow and quasi-physiological). EMG recordings were used to extract muscular synergies. Results indicate that the interaction with the robot very slightly alters healthy people patterns but, on the contrary, it may promote the emergency of physiological-like synergies on neurological patients.

Management of stroke patients submitted to botulinum toxin type A therapy: a Delphi survey of an Italian expert panel of specialist injectors.

BACKGROUND: Spasticity is a common disabling symptom of several neurological conditions including stroke. Botulinum toxin type A (BTX-A) injection represents the gold standard therapy for focal spasticity. Post-stroke management of patients receiving BTX-A therapy has been variously investigated, but general agreement on how and when to implement rehabilitation is lacking. AIM: To perform a national survey of experts on the most appropriate rehabilitation procedures after BTX-A therapy for the focal treatment of spasticity. DESIGN: The study employed the Delphi technique through the COSMO project (Consensus on Post-Injection Management in Post-stroke Spasticity). METHODS: Italian neurologists and physiatrists with experience in BTX-A therapy were selected to participate in the survey. Their anonymous opinions on key issues in treatment strategies in post-stroke spasticity were collected in three sequential rounds facilitated by a web platform. Consensus on a given issue was defined as agreed opinion by at least 66% of the survey participants. RESULTS: In all, 44 Italian experts were involved. Positive consensus was reached on the need to start rehabilitation during the first week after BTX-A injection therapy, with a rehabilitation program comprising both stretching combined with electrical stimulation and exercise therapy. Functional surgery may be considered only after 12-24 months in cases of BTX-A therapy failure. The use of commercial or custom-made orthoses in selected cases was recommended. The appropriate time interval between two BTX-A injections is 3-6 months, and clinical assessment should be performed 1 month after injection. CONCLUSION: The results of this national survey confirm that clinical experts on the use of BTX-A therapy for spasticity after stroke agree on the need to initiate rehabilitation treatment immediately after BTX-A injection: muscle stretching exercises, eventually combined with neuromuscular electrical stimulation, may enhance the effect of BTX-A therapy. Outcome after BTX-A therapy should be assessed at repeated follow-up visits. CLINICAL REHABILITATION IMPACT: This expert panel survey can provide guidance for clinicians in the assessment of patients treated with BTX-A therapy.

The anatomical foundations of acquired reading disorders: a neuropsychological verification of the dual-route model of reading.

In this study we investigated the neural correlates of acquired reading disorders through an anatomo-correlative procedure of the lesions of 59 focal brain damaged patients suffering from acquired surface, phonological, deep, undifferentiated dyslexia and pure alexia. Two reading tasks, one of words and nonwords and one of words with unpredictable stress position, were used for this study. We found that surface dyslexia was predominantly associated with left temporal lesions, while in phonological dyslexia the lesions overlapped in the left insula and the left inferior frontal gyrus (pars opercularis) and that pure alexia was associated with lesions in the left fusiform gyrus. A number of areas and white matter tracts, which seemed to involve processing along both the lexical and the sublexical routes, were identified for undifferentiated dyslexia. Two cases of deep dyslexia with relatively dissimilar anatomical correlates were studied, one compatible with Coltheart's right-hemisphere hypothesis (1980) whereas the other could be interpreted in the context of Morton and Patterson's (1980), multiply-damaged left-hemisphere hypothesis. In brief, the results of this study are only partially consistent with the current state of the art, and propose new and stimulating challenges; indeed, based on these results we suggest that different types of acquired dyslexia may ensue after different cortical damage, but white matter disconnection may play a crucial role in some cases.

A new scale for the assessment of performance and capacity of hand function in children with hemiplegic cerebral palsy: reliability and validity studies.

BACKGROUND: In hemiplegic children, the recognition of the activity limitation pattern and the possibility of grading its severity are relevant for clinicians while planning interventions, monitoring results, predicting outcomes. OBJECTIVE: Aim of the study is to examine the reliability and validity of Besta Scale, an instrument used to measure in hemiplegic children from 18 months to 12 years of age both grasp on request (capacity) and spontaneous use of upper limb (performance) in bimanual play activities and in ADL. DESIGN: Psychometric analysis of reliability and of validity of the Besta scale was performed. SETTING: Outpatient study sample METHODS: Reliability study: A sample of 39 patients was enrolled. The administration of Besta scale was video-recorded in a standardized manner. All videos were scored by 20 independent raters on subsequent viewing. 3 raters randomly selected from the 20-raters group rescored the same video two years later for intra-rater reliability. Intra and inter-rater reliability were calculated using Intraclass Correlation Coefficient (ICC) and Kendall's coefficient (K), respectively. Internal consistency reliability was assessed using Alpha's Chronbach coefficient. Validity study: a sample of 105 children was assessed 5 times (at t0 and 2, 3, 6 and 12 months later) by 20 independent raters. Each patient underwent at the same time to QUEST and Besta scale administration and assessment. Criterion validity was calculated using rho-Pearson coefficient. RESULTS: Reliability study: The inter-rater reliability calculated with Kendall's coefficient resulted moderate K=0.47. The intra-rater (or test-retest) reliability for 3 raters was excellent (ICC=0.927). The Cronbach's alpha for internal consistency was 0.972. Validity study: Besta scale showed a good criterion validity compared to QUEST increasing by age and severity of impairment. Rho Pearson's correlation coefficient r was 0.81 (P<0.0001). Limitations. Besta scales in infants finds hard to distinguish between mild to moderately impaired hand function. CONCLUSIONS: Besta scale scoring system is a valid and reliable tool, utilizable in a clinical setting to monitor evolution of unimanual and bimanual manipulation and to distinguish hand's capacity from performance.

Upper limb muscular activity and perceived workload during laryngoscopy: comparison of Glidescope(R) and Macintosh laryngoscopy in manikin: an observational study.

BACKGROUND: The interaction between operators and their working environment during laryngoscopy is poorly understood. Numerous studies have focused on the forces applied to the patient's airway during laryngoscopy, but only a few authors have addressed operator muscle activity and workload. We tested whether different devices (Glidescope(®) and Macintosh) use different muscles and how these differences affect the perceived workload. METHODS: Ten staff anaesthetists performed three intubations with each device on a manikin. Surface electromyography was recorded for eight single muscles of the left upper limb. The NASA Task Load Index (TLX) was administered after each experimental session to evaluate perceived workload. RESULTS: A consistent reduction in muscular activation occurred with Glidescope(®) compared with Macintosh for all muscles tested (mean effect size d=3.28), and significant differences for the upper trapezius (P=0.002), anterior deltoid (P=0.001), posterior deltoid (P=0.000), and brachioradialis (P=0.001) were observed. The overall NASA-TLX workload score was significantly lower for Glidescope(®) than for Macintosh (P=0.006), and the factors of physical demand (P=0.008) and effort (P=0.006) decreased significantly. CONCLUSIONS: Greater muscular activity and workload were observed with the Macintosh laryngoscope. Augmented vision and related postural adjustments related to using the Glidescope(®) may reduce activation of the operator's muscles and task workload.

Extensor hallucis longus transfer as an alternative to split transfer of the tibialis anterior tendon to correct equinovarus foot in hemiplegic patients without overactivity of tibialis anterior.

This study assessed if transfer of the extensor hallucis longus is a valid alternative treatment to split transfer of the tibialis anterior tendon in adult hemiplegic patients without overactivity of the tibialis anterior. One group of 15 patients had overactivity of tibialis anterior in the swing phase, and underwent the split transfer. A further group of 14 patients had no overactivity of tibialis anterior, and underwent transfer of extensor hallucis longus. All patients had lengthening of the tendo Achillis and tenotomies of the toe flexors. All were evaluated clinically and by three-dimensional gait analysis pre- and at one year after surgery. At this time both groups showed significant reduction of disability in walking. Gait speed, stride length and paretic propulsion had improved significantly in both groups. Dorsiflexion in the swing phase, the step length of the healthy limb and the step width improved in both groups, but only reached statistical significance in the patients with transfer of the extensor hallucis longus. There were no differences between the groups at one year after operation. When combined with lengthening of the tendo Achillis, transfer of the extensor hallucis longus can be a valid alternative to split transfer of the tibialis anterior tendon to correct equinovarus foot deformity in patients without overactivity of tibialis anterior.

The prevalence of antibodies to human herpesvirus 8 and hepatitis B virus in patients in two hospitals in Tanzania.

The aim of this study was to determine the seroprevalence of human herpesvirus 8 (HHV-8) and the immunization status for hepatitis B virus (HBV) infection in febrile patients in two districts of the United Republic of Tanzania. Between February and March 2007, blood samples were collected in Pemba Island and Tosamaganga from 336 outpatients and sent to the Virology Laboratory in Rome (Italy) for testing. HHV-8 DNA and HBV-DNA were amplified by two in-house molecular methods, anti-HHV-8 antibody titers were determined by an immunofluorescence assay (IFA), and anti-HCV, HBsAg, anti-HBs, and anti-HBc were evaluated by microplate enzyme immunoassay (MEIA). The seroprevalence of HHV-8 was 30.7% (96/313). In Pemba Island, the prevalence was lower than in Tosamaganga (14.4% vs. 46.3%). A higher prevalence of low titers of HHV-8 IgG (<1:80, 81%) was found among those under 5 years of age. HHV-8 DNA was detected in six seropositive patients (6.7%). The prevalence of HBsAg, anti-HBs, and anti-HBc was 4.3%, 37.6%, and 29.3%, respectively. Out of 277 patients, 70 had had a previous infection (25.3%). One case of occult hepatitis was found. The cover of hepatitis B vaccination was higher among children born after 2002 (66.7%) than in patients born before 2002. HHV-8 infection is endemic in Tanzania and the seroprevalence rate was higher in the mainland than on Pemba Island. The 3.9% percentage of HBsAg in children younger than 4 years of age suggests that increased efforts are required in order to achieve universal and compulsory immunization of children against HBV.

Cycling induced by functional electrical stimulation improves the muscular strength and the motor control of individuals with post-acute stroke. Europa Medicophysica-SIMFER 2007 Award Winner.

AIM: The aim of this study was to investigate the effectiveness of cycling induced by functional electrical stimulation (FES) in patients with postacute stroke. METHODS: Twenty postacute inpatients were recruited and were randomly shared in a control group (56+/-9.2 years old, 50.8+/-24.5 days post-stroke) performing the standard rehabilitation (SR) and a FES group (51+/-12 years old, 56.1+/-22.8 days post-stroke) performing FES cycling in addition to SR. Both the groups performed 3 hours of rehabilitation per day for 4 weeks. The FES cycling was applied daily for 35 minutes and quadriceps, hamstring, gluteus maximus and tibialis anterior of both the legs were stimulated. The two groups were compared by the following outcome measurements before and after treatment: maximum isometric voluntary contraction (MVC) of quadriceps, walking and sit-to-stand ability, motricity index, upright motor control test and trunk control test. RESULTS: After the treatment, the U-Mann-Whitney test demonstrated that the FES group produced a significantly higher increase of the muscular force produced by both the quadriceps during MVC with respect to the control group (P<0.05). Seventy percent of FES patients learned how to perform the sit to stand movement with three different rising speeds while no control patients develop the ability to perform the task properly. CONCLUSION: Rehabilitation including FES cycling was more effective in promoting muscle strength and motor recovery of the lower extremity than therapist-assisted SR alone. Tests on an enlarged number of patients are necessary for generalization before proposing FES cycling in the clinical rehabilitation of post-acute stroke patients.

Cardiac response to robotic assisted locomotion in normal subjects: a preliminary study.

Robotic assisted locomotion systems are recently gaining appreciation and diffusion as useful methods to rehabilitate individuals with lost sensorimotor function. Our aim was to evaluate potential changes in the autonomic nervous system activity (by ECG and spectral analysis), due to the experimental protocol, which include suspension of the subject to be instrumented on the system. A group of 10 normal subjects was studied during the rehabilitation protocol. Results showed a significant tachycardia and a reduced variance, during orthostatic stress induced by the suspension phase in comparison with sitting baseline condition but no significant increase of LF normalized power as it would be expected during a sympathetic activation.

Comparison of the Paracheck-Pf test with microscopy, for the confirmation of Plasmodium falciparum malaria in Tanzania.

Paracheck-Pf is a rapid, qualitative immuno-assay for the detection of Plasmodium falciparum-specific histidine-rich protein-2 in samples of human blood. The assay has now been evaluated, against the usual 'gold standard', microscopy, using blood samples from 1655 individuals in five districts of Tanzania, four of which experience frequent malaria outbreaks. The aim was to verify whether Paracheck-Pf could be a reliable tool for the confirmation of malaria outbreaks in such areas. The overall measurements of the assay's performance were good, with a sensitivity of 90.0%, a specificity of 96.6%, a positive predictive value of 88.9%, and a negative predictive value of 97.0% (with an estimated malaria prevalence of 23.3%). There was, however, marked variation between the study districts, the assay's performance being relatively poor where the test had been stored for 12 months at room temperature (23.5+/-3.5 degrees C). The assay was easy to perform in the field and could clearly be a valuable tool in remote areas and in emergency situations, such as the early detection of malaria outbreaks. The cost of the assay (U.S.$0.62/test at the time of the present study) is sufficiently low that its routine use in the confirmation of P. falciparum malaria might also be cost-effective, particularly in areas where there are no facilities for microscopy and/or where the first-line treatment of malaria is based on relatively expensive artemisinin-based combinations.

Indoors man-biting mosquitoes and their implication on malaria transmission in Mpwapwa and Iringa Districts, Tanzania.

Entomological surveys were carried out in six villages at different altitudes in Mpwapwa and Iringa Districts in central Tanzania in March 2002. A total of 1291 mosquitoes were collected. Of these, 887 mosquitoes were collected by light traps and 404 by indoor pyrethrum spray catch technique. Seventy-nine percent (1026) were Anopheles gambiae s.l., 0.2% (N = 3) were An. funestus, and 20.3% (N = 262) were Culex quinquefasciatus. Other species including Cx cinereus, An. coustani and Aedes spp accounted for 0.5% of the mosquito population. In Iringa, more mosquitoes were collected by pyrethrum spray catch than light trapping technique. The light trap catch: spray catch ratio in Iringa and Mpwapwa was 1:1.15 and 2.5:1, respectively. Indoor pyrethrum spray catch gave an overall estimate of An. gambiae density of 8 and 0.6 mosquitoes per room in Iringa and Mpwapwa, respectively, whereas light trap collections gave an overall respective density of An. gambiae of 63.9 and 2.9 mosquitoes per room. The densities of house entering mosquitoes were found to range from 0 to 135 in Iringa and from 2.6 to 3.5 per room in Mpwapwa. An.funestus mosquitoes were collected in Iringa only. None of the dissected An. gambiae collected in the two districts was infected with malaria sporozoites. Despite low mosquito densities and absence of infective mosquitoes in our study, the two districts are malaria epidemic prone, thus a continuous surveillance is critical for a prompt response to any impending outbreak. Further longitudinal studies are required to determine the transmission potential of the malaria mosquitoes in the two districts.