Severe Palsy Research Articles

Vestibular Schwannoma Complicated by Facial Paralysis: Considerations of Techniques and Timing for Facial Reanimation

To understand the risk factors for facial paralysis following vestibular schwannoma removal and determine the appropriate conditions for and timing of surgical intervention. Intraoperative facial nerve response to stimulation helps identify patients likely to have good facial function ( 0.1 mA). Patients with severe postoperative paralysis (HB V–VI) who fail to improve in the first 7–10 months are unlikely to develop good long-term facial function and surgical intervention may be considered as early as 6–7 months. Hypoglossal nerve transfer improves facial tone and motion; techniques preserving part of the hypoglossal nerve are preferred. Masseter nerve transfer is supplanting the hypoglossal nerve at many centers due to quicker reinnervation, easier activation, and lower morbidity. Facial reanimation with early nerve transfer should be considered for patients with severe paralysis failing to improve over the first 6 months following vestibular schwannoma removal.

Sequential neurological improvements after conservative treatment in patients with complete motor paralysis caused by cervical spinal cord injury without bone and disc injury.

OBJECTIVE This study investigated neurological improvements after conservative treatment in patients with complete motor paralysis caused by acute cervical spinal cord injury (SCI) without bone and disc injury. METHODS This study was retrospective. The authors evaluated neurological outcomes after conservative treatment of 62 patients with complete motor paralysis caused by cervical SCI without bone and disc injury within 72 hours after trauma. The sequential changes in their American Spinal Injury Association Impairment Scale (AIS) grades were reviewed at follow-up 24-72 hours, 1 week, and 1, 3, and 6 months after treatment. RESULTS Of the 31 patients with a baseline AIS grade of A, 2 (6.5%) patients improved to grade B, 5 (16.1%) improved to grade C, and 2 (6.5%) improved to grade D by the 6-month follow-up. The 22 (71.0%) patients who remained at AIS grade A 1 month after injury showed no neurological improvement at the 6-month follow-up. Of the 31 patients with a baseline AIS grade of B, 12 (38.7%) patients showed at least a 1-grade improvement at the 1-month follow-up; 11 (35.5%) patients improved to grade C and 16 (51.6%) patients improved to grade D at the 6-month follow-up. CONCLUSIONS Even in patients with complete motor paralysis caused by cervical SCI without bone and disc injury within 72 hours after trauma, approximately 30% of the patients with an AIS grade of A and 85% of the patients with an AIS grade B improved neurologically after conservative treatment. It is very important to recognize the extent of neurological improvement possible with conservative treatment, even for severe complete motor paralysis.

Enterovirus D68 in a community hospital: A test-negative case-control study

Background: In August 2014, a large North American outbreak of enterovirus D68 (EV-D68) was observed in association with severe respiratory illnesses in children as well as a possible association with acute flaccid paralysis. The full spectrum of clinical illness associated with EV-D68 is not well known. Objective: To compare children positive and negative for EV-D68 presenting to a community hospital during the North American outbreak in the fall of 2014. Methods: Consecutive nasopharyngeal swabs obtained from children (<18 years old) presenting to a large community hospital with respiratory symptoms in the fall of 2014 were tested for EV-D68. We conducted a test-negative case-control study between EV-D68 positive and EV-D68 negative children to describe the clinical and outcome characteristics. Controls were limited to children who had a nasopharyngeal swab obtained. EV-D68 indeterminate cases were excluded from the primary analysis. All nasopharyngeal swabs were referred to a reference laboratory for polymerase chain reaction testing and identification of EV-D68 through targeting the 5'NTR region and confirmed by amplifying the VP1 gene for serotype determination. Results: Of the 48 children tested there were 9 positive, 36 negative, and 3 indeterminate for EV-D68. Six of the 9 identified cases of EV-D68 were identified in the first week of testing (September 11–18, 2014). There were 35 children (78%) admitted to hospital for ≥1 day. EV-D68 infected children were significantly older (5.2 versus 2.5 years, p = 0.03). They were more likely to be concurrently taking asthma medications (44% versus 11%, p = 0.04) and receiving treatment with salbutamol (100% versus 58%, p = 0.02). There were no cases of severe respiratory distress or acute flaccid paralysis. Three EV-D68 infected children (33%) had viral co-infections identified. Conclusion: This study of a community hospital experience during the fall of 2014 demonstrates a series of mild illnesses from both EV-D68 positive and negative children. EV-D68 isolation was associated with age and asthmatic treatment in children.

Effectiveness of Alpha Chymotrypsin on the Treatment of Severe Paralysis due to Bungarus Multicinctus Snakebite

Background: In Vietnam, there are two main species of Bungarus: Bungarus multicinctus and Bungarus candidus. Trypsin is a serine protease digestive enzyme that has demonstrated efficacy in some of Elapidae envenomations. After their experiments with dogs and mice, Hsiung Yu-Liang et al. concluded the local injection of trypsin can be used in clinical practice as a new and effective therapy for snakebite. We report a case of successful application of alphachymotrypsin, a related enzyme, in the treatment of severe paralysis due to B. multicinctus snakebite. Case presentation: A 38-year-old man was bitten on his left hand by B. multicinctus. Two hours after the bite, the patient developed a sore throat, diffuse myalgia, and progressive paralysis. Since antivenom was not available, we decided to administer alphachymotrypsin after the risks and benefits were carefully discussed. A dose of 5000 IU alphachymotrypsin was administered by the IM route at 24 and 31 hours after bite. At the time of the first dose of alphachymotrypsin, muscle power was 0/5. The muscle power improved rapidly, from 0/5 (24 hours) to 2/5 (at 44 hours). After that, additional doses of 10.000 IU of alphachymotrypsin were administered at 45, 55, 69, 75, 94 and 100 hour after the bite; the muscle power increased gradually then to 3/5 (66 hours), 4/5 (75 hours), and 5/5 (97 hours). Discussion: The severity of the patient can be estimated through some factors as following: the heavier and longer the nake, the more severe the threat, time from bite to symptoms: the sooner the more severe, the level of paralysis, and the level of hyponatremia. According to these signs, the patient was classified under the severe group because the snake was long and heavy (1.5 m and 300 gr), symtoms appeared right after 2 hours after the bite, and level of paralysis was 0/5 17 hours after the bite. The mild hyponatremia could be related to either a minor B. multicinctus envenomation, which is unlikely given the severity of the other clinical findings, or the effectiveness of alphachymotrysin. This hypothesis requires further investigation, both mechanistically and clinically. Conclusion: The use of alphachymotrypsin was associated with a shortening of the need for mechanical ventilation, length of ICU stay, and a reduced extent of hyponatremia in a patient with severe B. multicinctus envenomation.

Evaluation of the prognostic value of multimodal intraoperative monitoring in posterior fossa surgery patients with cerebellopontine angle tumors.

The aim of this study was to compare the outcomes of four intraoperative monitoring approaches in order to compare their prognostic value in surgical complications of the facial nerve. This quasi-experimental study was conducted on 25 patients with Cerebellopontine Angle (CPA) tumors, who were hospitalized in the Valiasr Hospital, affiliated to the Arak University of Medical Sciences, Arak, Iran. The degree of the facial nerve paralysis was assessed based on the House-Brackmann (HB) facial nerve grading system. The Orbicularis oris and Oculi muscles were evaluated by electromyography (EMG) before and after the surgery. Monitoring the facial nerve was performed by the EMG, Facial Nerve Antidromic Potentials (FNAPs), Transcranial Electrical Stimulation (TES), and Brainstem Auditory Evoked Potentials (BAEPs) methods. The mean HB score was 0.36.6±5.83, indicating that the function of the facial muscle was abnormal in all the patients pre-surgery. The comparison of the four monitoring approaches six months after surgery showed that the predictive value of facial nerve TES was higher than the other approaches (P<0.005). Furthemroe, 4% of the patients showed normal function in the facial muscle after the surgery. In addition, 8%, 56%, and 32% of the patients had mild abnormalities, moderate to severe paralysis in the facial muscles, and severe facial nerve dysfunction, respectively. In summary, 36% of the patients showed a mild abnormalities in the follow-up period, and full recovery was observed in 28% of the cases. In conclusion, the transcranial motor evoked potential (TCMEP) is a useful method for monitoring the facial nerve during the surgery along with the continuous EMG recordings.

A Brief History of the Encoding of Hand Position by the Cerebral Cortex: Implications for Motor Control and Cognition.

Encoding hand position by the cerebral cortex is essential not only for the neural representation of the body image but also for different actions based on eye-hand coordination. These include reaching for visual objects as well as complex movement sequences, such as tea-making, tool use, and object construction, among many others. All these functions depend on a continuous refreshing of the hand position representation, relying on both predictive signaling and afferent information. The hand position influence on neural activity in the parietofrontal system, together with eye position signals, are the basic elements of an eye-hand matrix from which all the above functions can emerge and could be regarded as key features of a network with several entry points, command nodes and outflow pathways, as confirmed by the discovery of a direct parietospinal projection for the control of hand action. The integrity of this system is crucial for daily life, as testified by the consequences of cortical lesions, spanning from severe paralysis to complex forms of apraxia. In this review, I will sketch my personal understanding of the scientific and conceptual trajectory of a line of investigation with many unexpected influences on cortical function and disease, from motor behavior to cognition.

Effect of the combination of motor imagery and electrical stimulation on upper extremity motor function in patients with chronic stroke: preliminary results.

Background:The combination of motor imagery (MI) and afferent input with electrical stimulation (ES) enhances the excitability of the corticospinal tract compared with motor imagery alone or electrical stimulation alone. However, its therapeutic effect is unknown in patients with hemiparetic stroke. We performed a preliminary examination of the therapeutic effects of MI + ES on upper extremity (UE) motor function in patients with chronic stroke.Methods:A total of 10 patients with chronic stroke demonstrating severe hemiparesis participated. The imagined task was extension of the affected finger. Peripheral nerve electrical stimulation was applied to the radial nerve at the spiral groove. MI + ES intervention was conducted for 10 days. UE motor function as assessed with the Fugl–Meyer assessment UE motor score (FMA-UE), the amount of the affected UE use in daily life as assessed with a Motor Activity Log (MAL-AOU), and the degree of hypertonia in flexor muscles as assessed with the Modified Ashworth Scale (MAS) were evaluated before and after intervention. To assess the change in spinal neural circuits, reciprocal inhibition between forearm extensor and flexor muscles with the H reflex conditioning-test paradigm at interstimulus intervals (ISIs) of 0, 20, and 100 ms were measured before and after intervention.Results:UE motor function, the amount of the affected UE use, and muscle hypertonia in flexor muscles were significantly improved after MI + ES intervention (FMA-UE: p < 0.01, MAL-AOU: p < 0.01, MAS: p = 0.02). Neurophysiologically, the intervention induced restoration of reciprocal inhibition from the forearm extensor to the flexor muscles (ISI at 0 ms: p = 0.03, ISI at 20 ms: p = 0.03, ISI at 100 ms: p = 0.01).Conclusion:MI + ES intervention was effective for improving UE motor function in patients with severe paralysis.

Severe paralysis after spinal hemangioblastoma resection: A case report

Severe paralysis after spinal hemangioblastoma resection: A case report

Complete Hypokalemic Quadriparesis as a First Presentation of Sjögren Syndrome.

Rationale:We hope to increase awareness that hypokalemic paralysis may be the first presentation of Sjögren syndrome, for which potassium-sparing diuretics can be an effective adjunct to potassium replenishment.Presenting concerns:A 73-year-old female presented to a peripheral hospital with quadriparesis and a critically low serum potassium of 1.6 mmol/L with U waves on the electrocardiogram (ECG). The initial arterial blood gas showed a pH of 7.19, bicarbonate of 13 mEq/L, and a CO2 of 35 mm Hg. Over the next 6 days, she was administered a total of 450 mEq of potassium supplements. Despite this, her potassium never increased above 2.9 mmol/L and was thus transferred to the University Hospital for further management. On arrival, her vital signs were within normal limits. Her only other symptoms were fatigue and ocular dryness. Physical exam showed slightly weakened quadriceps muscles bilaterally, graded 4/5. Examination was otherwise unremarkable. Admission investigations included a potassium of 2.8 mmol/L, chloride 118 mmol/L, sodium 136 mmol/L, and eGFR 48 mL/min/1.73 m2. Renin aldosterone ratio was normal.Diagnoses:Distal renal tubular acidosis (RTA) was diagnosed based on a normal anion gap metabolic acidosis, positive urine anion gap, and elevated urine potassium to creatinine ratio. Investigation of underlying causes revealed a positive Antinuclear antibody (ANA), elevated rheumatoid factor, and high anti-Ro/SSA titre which directed us toward a unifying diagnosis of Sjögren syndrome. A renal biopsy was undertaken as an outpatient and demonstrated severe interstitial nephritis with acute and chronic components, parenchymal scarring, atrophy, and small vessel arteriosclerosis.Interventions:In the acute setting, the patient was treated with bicarbonate and amiloride in addition to potassium supplementation.Outcomes:The patient’s hypokalemic paralysis and metabolic acidosis were corrected.Lessons Learned:Severe hypokalemic paralysis in distal RTA associated with Sjögren syndrome can be successfully treated with amiloride in addition to potassium supplementation. We also review the literature on the aberrancies seen in H+ATPase, Band 3, Pendrin, and carbonic anhydrase that may underlie the pathogenesis of distal RTA in Sjögren syndrome.

The vertical balance management system is more synchronized in children with cerebral paralysis than in healthy children

Introduction. All forms of infantile cerebral paralysis involve motor function defects. In clinical practice, the stabilometrics method is widely used due to its ability to perform detailed analyses of the mechanisms of disturbance and restoration of postural control in patients with various cerebral lesions.&#x0D; Aim. The study aimed to analyze the parameters of orthostatic balance in practically healthy children and in children with motor disorders caused by infantile cerebral paralysis of various severities.&#x0D; Material and methods. We examined 6- to 12-year-old children with mild and severe cerebral paralysis and impaired vertical postural control with a preserved ability to self-balance in the principal posture. Each group examined for comparison comprised 10 patients (children with infantile cerebral paralysis, and impaired vertical postural control) and 10 healthy children in the same age range. The stabilometrics method was used, and the statistical evaluation included correlation and regression analyses.&#x0D; Results. The results revealed that in comparison with the healthy children, the patient group exhibited a decrease in the vertical postural stability, which manifested as pronounced deviations from the nominal values of the stabilometric parameters. However, a strong correlation between the parameters of S, LFS, and the amplitude A of the pressure center was revealed, which significantly exceeded that of the healthy children, being most pronounced in cases of severe infantile cerebral paralysis. This indicates a more ordered center of pressure trajectory and, consequently, a higher synchronization of the vertical balance management system in children with infantile cerebral paralysis compared with that in healthy children.&#x0D; Conclusion. The use of correlation and regression analysis to study the vertical balance of patients provides a deeper understanding of the mechanisms used by the postural control system in patients with infantile cerebral paralysis to maintain a complex multilevel structure of the musculoskeletal system in equilibrium in the process of standing still. Increased ordering of the center of pressure trajectory of statokinesiograms of children with infantile cerebral paralysis can be considered as a dynamic indicator of postural control deficiency.

Decoding spoken phonemes from sensorimotor cortex with high-density ECoG grids

For people who cannot communicate due to severe paralysis or involuntary movements, technology that decodes intended speech from the brain may offer an alternative means of communication. If decoding proves to be feasible, intracranial Brain-Computer Interface systems can be developed which are designed to translate decoded speech into computer generated speech or to instructions for controlling assistive devices. Recent advances suggest that such decoding may be feasible from sensorimotor cortex, but it is not clear how this challenge can be approached best. One approach is to identify and discriminate elements of spoken language, such as phonemes. We investigated feasibility of decoding four spoken phonemes from the sensorimotor face area, using electrocorticographic signals obtained with high-density electrode grids. Several decoding algorithms including spatiotemporal matched filters, spatial matched filters and support vector machines were compared. Phonemes could be classified correctly at a level of over 75% with spatiotemporal matched filters. Support Vector machine analysis reached a similar level, but spatial matched filters yielded significantly lower scores. The most informative electrodes were clustered along the central sulcus. Highest scores were achieved from time windows centered around voice onset time, but a 500 ms window before onset time could also be classified significantly. The results suggest that phoneme production involves a sequence of robust and reproducible activity patterns on the cortical surface. Importantly, decoding requires inclusion of temporal information to capture the rapid shifts of robust patterns associated with articulator muscle group contraction during production of a phoneme. The high classification scores are likely to be enabled by the use of high density grids, and by the use of discrete phonemes. Implications for use in Brain-Computer Interfaces are discussed.

S.24.01 - Fully implanted brain signal recording device for communication in severe paralysis reveals feasibility of chronic home use of neuronal activity

S.24.01 - Fully implanted brain signal recording device for communication in severe paralysis reveals feasibility of chronic home use of neuronal activity

Locked Out.

Brain-computer interfaces (BCIs) can enable communication for persons in severe paralysis including locked-in syndrome (LIS); that is, being unable to move or speak while aware. In cases of complete loss of muscle control, termed "complete locked-in syndrome," a BCI may be the only viable solution to restore communication. However, a widespread ignorance regarding quality of life in LIS, current BCIs, and their potential as an assistive technology for persons in LIS, needlessly causes a harmful situation for this cohort. In addition to their medical condition, these persons also face social barriers often perceived as more impairing than their physical condition. Through social exclusion, stigmatization, and frequently being underestimated in their abilities, these persons are being locked out in addition to being locked-in. In this article, we (1) show how persons in LIS are being locked out, including how key issues addressed in the existing literature on ethics, LIS, and BCIs for communication, such as autonomy, quality of life, and advance directives, may reinforce these confinements; (2) show how these practices violate the United Nations Convention on the Rights of Persons with Disabilities, and suggest that we have a moral responsibility to prevent and stop this exclusion; and (3) discuss the role of BCIs for communication as one means to this end and suggest that a novel approach to BCI research is necessary to acknowledge the moral responsibility toward the end users and avoid violating the human rights of persons in LIS.

Gene Therapy-Induced Antigen-Specific Tregs Inhibit Neuro-inflammation and Reverse Disease in a Mouse Model of Multiple Sclerosis.

The devastating neurodegenerative disease multiple sclerosis (MS) could substantially benefit from an adeno-associated virus (AAV) immunotherapy designed to restore a robust and durable antigen-specific tolerance. However, developing a sufficiently potent and lasting immune-regulatory therapy that can intervene in ongoing disease is a major challenge and has thus been elusive. We addressed this problem by developing a highly effective and robust tolerance-inducing in vivo gene therapy. Using a pre-clinical animal model, we designed a liver-targeting gene transfer vector that expresses full-length myelin oligodendrocyte glycoprotein (MOG) in hepatocytes. We show that by harnessing the tolerogenic nature of the liver, this powerful gene immunotherapy restores immune tolerance by inducing functional MOG-specific regulatory T cells (Tregs) in vivo, independent of major histocompatibility complex (MHC) restrictions. We demonstrate that mice treated prophylactically are protected from developing disease and neurological deficits. More importantly, we demonstrate that when given to mice with preexisting disease, ranging from mild neurological deficits to severe paralysis, the gene immunotherapy abrogated CNS inflammation and significantly reversed clinical symptoms of disease. This specialized approach for inducing antigen-specific immune tolerance has significant therapeutic potential for treating MS and other autoimmune disorders.

Calpain-Dependent Degradation of Nucleoporins Contributes to Motor Neuron Death in a Mouse Model of Chronic Excitotoxicity.

Glutamate-mediated excitotoxicity induces neuronal death by altering various intracellular signaling pathways and is implicated as a common pathogenic pathway in many neurodegenerative diseases. In the case of motor neuron disease, there is significant evidence to suggest that the overactivation of AMPA receptors due to deficiencies in the expression and function of glial glutamate transporters GLT1 and GLAST plays an important role in the mechanisms of neuronal death. However, a causal role for glial glutamate transporter dysfunction in motor neuron death remains unknown. Here, we developed a new animal model of excitotoxicity by conditionally deleting astroglial glutamate transporters GLT1 and GLAST in the spinal cords of mice (GLAST+/-/GLT1-cKO). GLAST+/-/GLT1-cKO mice (both sexes) exhibited nuclear irregularity and calpain-mediated degradation of nuclear pore complexes (NPCs), which are responsible for nucleocytoplasmic transport. These abnormalities were associated with progressive motor neuron loss, severe paralysis, and shortened lifespan. The nuclear export inhibitor KPT-350 slowed but did not prevent motor neuron death, whereas long-term treatment of the AMPA receptor antagonist perampanel and the calpain inhibitor SNJ-1945 had more persistent beneficial effects. Thus, NPC degradation contributes to AMPA receptor-mediated excitotoxic motor neuronal death, and preventing NPC degradation has robust protective effects. Normalization of NPC function could be a novel therapeutic strategy for neurodegenerative disorders in which AMPA receptor-mediated excitotoxicity is a contributory factor.SIGNIFICANCE STATEMENT Despite glial glutamate transporter dysfunction leading to excitotoxicity has been documented in many neurological diseases, it remains unclear whether its dysfunction is a primary cause or secondary outcome of neuronal death at disease state. Here we show the combined loss of glial glutamate transporters GLT1 and GLAST in spinal cord caused motor neuronal death and hindlimb paralysis. Further, our novel mutant exhibits the nuclear irregularities and calpain-mediated progressive nuclear pore complex degradation. Our study reveals that glial glutamate transporter dysfunction is sufficient to cause motor neuronal death in vivo.

Vestibular Restoration and Adaptation in Vestibular Neuritis and Ramsay Hunt Syndrome With Vertigo.

To evaluate vestibular restoration and the evolution of the compensatory saccades in acute severe inflammatory vestibular nerve paralysis, including vestibular neuritis and Ramsay Hunt syndrome with vertigo. Prospective. Tertiary referral center. Vestibular neuritis (n = 18) and Ramsay Hunt syndrome patients with vertigo (n = 13) were enrolled. After treatment with oral corticosteroids, patients were followed up for 6 months. Functional recovery of the facial nerve was scored according to the House-Brackman grading system. Caloric and video head impulse tests were performed in every patient at the time of enrolment. Subsequently, successive video head impulse test (vHIT) exploration was performed at the 1, 3, and 6-month follow-up. Eighteen patients with vestibular neuritis and 13 with Ramsay Hunt syndrome and associated vertigo were included. Vestibular function was significantly worse in patients with Ramsay Hunt syndrome than in those with vestibular neuritis. Similar compensatory saccades velocity and latency values were observed in both groups, in both the caloric and initial vHIT tests. Successive vHIT results showed a significantly higher vestibulo-ocular reflex gain recovery in vestibular neuritis patients than in Ramsay Hunt syndrome patients. A significantly faster reduction in the latency, velocity, and organization of the compensatory saccades was observed in neuritis than in Ramsay Hunt syndrome patients. In addition to the recovery of the vestibulo-ocular reflex, the reduction of latency, velocity and the organization of compensatory saccades play a role in vestibular compensation.

Correction of a splicing defect in a mouse model of congenital muscular dystrophy type 1A using a homology-directed-repair-independent mechanism.

Splice-site defects account for about 10% of pathogenic mutations that cause Mendelian diseases. Prevalence is higher in neuromuscular disorders (NMDs), owing to the unusually large size and multi-exonic nature of genes encoding muscle structural proteins. Therapeutic genome editing to correct disease-causing splice-site mutations has been accomplished only through the homology-directed repair pathway, which is extremely inefficient in postmitotic tissues such as skeletal muscle. Here we describe a strategy using nonhomologous end-joining (NHEJ) to correct a pathogenic splice-site mutation. As a proof of principle, we focus on congenital muscular dystrophy type 1A (MDC1A), which is characterized by severe muscle wasting and paralysis. Specifically, we correct a splice-site mutation that causes the exclusion of exon 2 from Lama2 mRNA and the truncation of Lama2 protein in the dy2J/dy2J mouse model of MDC1A. Through systemic delivery of adeno-associated virus (AAV) carrying clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 genome-editing components, we simultaneously excise an intronic region containing the mutation and create a functional donor splice site through NHEJ. This strategy leads to the inclusion of exon 2 in the Lama2 transcript and restoration of full-length Lama2 protein. Treated dy2J/dy2J mice display substantial improvement in muscle histopathology and function without signs of paralysis.

Stroke lesion location influences the decoding of movement intention from EEG.

Recent studies have demonstrated the efficacy of brain-machine interfaces (BMI) for motor rehabilitation after stroke, especially for those patients with severe paralysis. However, a cerebro-vascular accident can affect the brain in many different manners, and lesions in diverse areas, even from significantly different volumes, can lead to similar or equal motor deficits. The location of the insult influences the way the brain activates when moving or attempting to move a paralyzed limb. Since the essence of a rehabilitative BMI is to precisely decode motor commands from the brain, it is crucial to characterize how lesion location affects the measured signals and if and how it influences BMI performance. This paper compares the performances of an electroencephalography (EEG)-based movement intention decoder in two groups of severely paralyzed chronic stroke patients: 14 with subcortical lesions and 14 with mixed (i.e., cortical and subcortical) lesions. We show that the lesion location influences the performance of the BMI when decoding the movement attempts of the paretic arm. The obtained results underline the need for further developments for a better individualization of BMI-based rehabilitative therapies for stroke patients.

Estimated Prevalence of the Target Population for Brain-Computer Interface Neurotechnology in the Netherlands

Background. People who suffer from paralysis have difficulties participating in society. Particularly burdensome is the locked-in syndrome (LIS). LIS patients are not able to move and speak but are cognitively healthy. They rely on assistive technology to interact with the world and may benefit from neurotechnological advances. Optimal research and design of such aids requires a well-defined target population. However, the LIS population is poorly characterized and the number of patients in this condition is unknown. Objective. Here we estimated and described the LIS patient population in the Netherlands to define the target population for assistive (neuro)technology. Methods. We asked physicians in the Netherlands if they had patients suffering from severe paralysis and communication problems in their files. Physicians responding affirmatively were asked to fill out a questionnaire on the patients’ status. Results. We sent out 9570 letters to general practitioners (GPs), who reported 83 patients. After first screening, the GPs of 46 patients received the questionnaire. Based on the responses, 26 patients were classified as having LIS. Extrapolation of these numbers resulted in a prevalence of 0.73 patients per 100 000 inhabitants. Notable results from the questionnaire were the percentage of patients with neuromuscular disease (>50%) and living at home (>70%). Conclusions. We revealed an etiologically diverse group of LIS patients. The functioning and needs of these patients were, however, similar and many relied on assistive technology. By characterizing the LIS population, our study may contribute to optimal development of assistive (neuro)technology.

Risk factors for severe dysphagia in acute cervical spinal cord injury.

A retrospective, consecutive case series. The relationship between dysphagia and acute cervical spinal cord injury (CSCI) has been recently reported; however, the cause and mechanism of dysphagia are still not well understood. No definitive factors have yet been established according to multivariate analysis. The objective is to elucidate the incidence and risk factors of dysphagia in patients with acute CSCI. Spinal Injuries Center, Fukuoka, Japan. A total of 298 patients with acute CSCI, who were evaluated for neurological impairment within 3 days after injury, were reviewed. CSCI patients with tube dependence due to obvious aspiration after injury were defined as having dysphagia. The factors postulated to increase the risk for dysphagia, including the patient's age, sex, American Spinal Injury Association (ASIA) impairment scale at 3 days after injury, level of injury, tracheostomy and operative treatment, were analyzed using a multiple logistic regression model. Of 298 patients, 21 were suffering from severe dysphagia after acute CSCI (7.0%). Of these 21 patients, 12 (57%) had CSCI at the C3-C4 level. Multivariable logistic regression analysis revealed that old age (>72 years), severe ASIA impairment scale (A or B) and presence of tracheostomy were significant risk factors of dysphagia. Level of injury ⩾C3-C4 was not a significant risk factor after adjustment for several potential confounders. The incidence of severe dysphagia associated with aspiration was 7%. Old age, severe paralysis and presence of tracheostomy may be the risk factors for dysphagia. The risk for dysphagia should be evaluated to prevent aspiration pneumonia.