A Unilateral Robotic Knee Exoskeleton to Assess the Role of Natural Gait Assistance in Hemiparetic Patients

Background: Hemiparetic gait is characterized by strong asymmetries that could severely affect the quality of life of stroke survivors. This asymmetry is due to motor deficits in the paretic leg and the resulting compensations in the non-paretic limb. In this study, we aim to evaluate the effect of actively promoting gait symmetry in hemiparetic patients by assessing the behavior of both paretic and non-paretic lower limbs. This paper introduces the design and validation of the REFLEX prototype, a unilateral active Knee-Ankle-Foot Orthosis able to naturally assist the paretic limb of hemiparetic patients during gait.Methods: REFLEX uses an Adaptive Frequency Oscillator to estimate the continuous gait phase of the non-paretic limb. Based on this estimation, the device synchronically assists the paretic leg following two different control strategies: (1) Replicating the movement of the sound leg or (2) Inducing a healthy gait pattern on the paretic leg. Technical validation of the system was implemented on three healthy subjects, while the effect of the generated assistance was assessed in three stroke patients. Results: Preliminary results proved the feasibility of the REFLEX prototype to assist gait by reinforcing symmetry. They also pointed out that the assistance of the paretic leg resulted in a decrease of the compensatory strategies developed by the non-paretic limb to achieve a functional gait. Notably, better results were attained when the assistance was provided according to a standard healthy pattern, which initially might suppose a lower symmetry but enabled a healthier evolution of the motion of the non-paretic limb.Conclusions: This work presents the preliminary validation of the REFLEX prototype, a unilateral knee exoskeleton for gait assistance in hemiparetic patients. The experimental results indicate that assisting the paretic leg of hemiparetic patients based on the movement of their non-paretic one is a valuable strategy for reducing the compensatory mechanisms developed by their sound limb.

A Septuagenarian With Progressive Hemiparesis

A 78-year-old man with no pertinent medical history sought care for an 18-month history of progressive right lower extremity weakness, gait impairment, and falls. On neurologic examination, he had a hemiparetic gait. He had normal higher cognitive function and cranial nerve function. Motor examination showed decreased bulk over the right hand with no fasciculations, mild spasticity over the right leg, and right hemiparesis with an upper motor neuron pattern. Deep tendon reflexes were brisk throughout his limbs, and he had an extensor plantar reflex on the right side. He had impaired vibratory sense at the toes, with otherwise normal sensory and coordination examinations. Magnetic resonance imaging (MRI) of the brain showed ovoid periventricular and punctate subcortical and deep white matter T2 hyperintense foci. Some of these had corresponding T1 hypointensity. MRI of the cervical spine showed 1 eccentrically located T2 hyperintense lesion over the right lateral aspect of C2. Cerebrospinal fluid analysis showed no pleocytosis, an increased protein concentration of 66 mg/dL, and 4 unique oligoclonal bands. A diagnosis of primary progressive multiple sclerosis, very late onset, was made. With any diagnosis of late-onset multiple sclerosis, a decision about whether multiple sclerosis disease-modifying agents are indicated should be carefully considered. Our older patient had a progressive disease course, and neuroimaging studies did not reveal evidence of active disease. Based on this, a decision was made to monitor him clinically and radiologically. Management of spasticity with regular daily stretching exercises was discussed with him. A first clinical manifestation of multiple sclerosis can occur at a later-than-typical age. Most studies consider an onset at age 50 years or older to be late-onset multiple sclerosis, whereas first symptoms occurring at age 60 years or older are commonly referred to as very late–onset MS.

A Brake-Based Overground Gait Rehabilitation Device for Altering Propulsion Impulse Symmetry

This paper introduces a new device for gait rehabilitation, the gait propulsion trainer (GPT). It consists of two main components (a stationary device and a wearable system) that work together to apply periodic stance-phase resistance as the user walks overground. The stationary device provides the resistance forces via a cable that tethers the user’s pelvis to a magnetic-particle brake. The wearable system detects gait events via foot switches to control the timing of the resistance forces. A hardware verification test confirmed that the GPT functions as intended. We conducted a pilot study in which one healthy adult and one stroke survivor walked with the GPT with increasing resistance levels. As hypothesized, the periodic stance-phase resistance caused the healthy participant to walk asymmetrically, with greatly reduced propulsion impulse symmetry; as GPT resistance increased, the walking speed also decreased, and the propulsion impulse appeared to increase for both legs. In contrast, the stroke participant responded to GPT resistance by walking faster and more symmetrically in terms of both propulsion impulse and step length. Thus, this paper shows promising results of short-term training with the GPT, and more studies will follow to explore its long-term effects on hemiparetic gait.

Gait patterns in ischemic and hemorrhagic post-stroke patients with delayed access to physiotherapy

Objectives: (1) To assess the effects of a conventional, delayed physiotherapy protocol used by Ischemic Stroke (IS) and Hemorrhagic Stroke (HS) post-stroke patients, in their electromyographic activation patterns during hemiparetic gait; and (2) to study whether this protocol may improve the functional abilities in this population. Methods: This is an observational, descriptive, and analytical quasi-experimental trial. Forty patients with unilateral IS ([Formula: see text]) and HS ([Formula: see text]) stroke were recruited; the stroke involved the motor cortex or sub-cortical areas, and the patients were able to walk independently. Interventions with standard protocols of physiotherapy were carried out. Evaluations (clinical and gait assessment) were performed at the time of admission and at the end of the protocol. Outcome measures include Stroke Impact Scale, Timed Up and Go Test, and gait electromyographic evaluation. Results: Only IS patients (with an average of [Formula: see text] months delayed access to physiotherapy rehabilitation) had improvements in Timed Up and Go Test (change in [Formula: see text][Formula: see text]seg [Formula: see text]) and presented an anticipation of the onset in Upper leg muscles after the intervention. BF ([Formula: see text]), ST ([Formula: see text]), and RF ([Formula: see text]), started their recruitment (onset) earlier at the swing phase of the gait cycle, which is more similar to the normal pattern (grey shadow). IS and HS ([Formula: see text] months since last stroke) patients presented higher electromyographic activation, after physiotherapy, of the posterior leg muscles (gastrocnemius, semitendinosus and biceps femoris) during stance phase ([Formula: see text]). Conclusion: IS patients had improvements after delayed conventional physiotherapy. For HS limited response to intervention was observed.

Oxygen Cost During Walking in Individuals With Stroke: Hemiparesis Versus Cerebellar Ataxia

Background. Understanding the factors that limit mobility in stroke patients is fundamental for proposing appropriate rehabilitation strategies. A high oxygen cost during walking (Cw) has a strong impact on the community ambulation of hemiparetic patients. The Cw in poststroke cerebellar ataxia is poorly evaluated, unlike hemiparetic gait. Objective. To compare the oxygen cost/self-selected walking speed (S) relationship in stroke individuals with cerebellar ataxia or hemiparetic gait. Methods. Thirty-three subjects were included (14 cerebellar stroke, 19 hemispheric stroke), with stroke confirmed by brain imaging and able to walk without human assistance. We measured Cw using the Metamax3B. The relationship between Cw and self-selected walking speed was modelled by logistic regression and then compared between the cerebellar and hemispheric groups. Results. No significant difference was found between the 2 groups for all characteristics of the population, except motor impairments, spasticity, and ataxia ( P < .01). We identified 2 separate Cw/S relationships with different logistic regression equations for the 2 groups. Faster than 0.4 m s−1, Cw was 30.6% to 39.9% higher in patients with cerebellar stroke in comparison with hemispheric stroke individuals. The Cw was correlated with ataxia ( r = 0.88; P < .001) in the cerebellar group, whereas there was a correlation with motor impairments ( r = −0.61; P < .01), spasticity ( r = 0.59; P < .01), and ataxia ( r = 0.81; P < .01) in hemispheric stroke individuals. Conclusion. The Cw in poststroke cerebellar ataxia is significantly higher compared with hemiparetic patients at an equivalent walking speed. The impact on community walking needs to be explored in stroke survivors with cerebellar stroke.

COL4A1-related autosomal recessive encephalopathy in 2 Turkish children

ObjectiveThis study presents the neurologic phenotypes of 2 brothers with a novel homozygous COL4A1 mutation that was identified in a large Turkish consanguineous cohort of neurogenetic diseases.MethodsWhole-exome sequencing and bioinformatic analysis of consanguineous families with children affected by early-onset, neurogenetic disorders was performed using the RD-Connect Genome-Phenome Analysis Platform. We also performed clinical, EEG, and neuroimaging analyses in unaffected siblings and parents.ResultsWe have identified a homozygous missense mutation in COL4A1 (p.Gly1278Ser, NM_001845.5:c.3832G>T) in 2 siblings affected by small vessel brain disease with periventricular leukoencephalopathy and ocular defects. Presenting symptoms included mild weakness, hemiparetic gait, pyramidal findings, and seizures, whereas their intellectual and behavioral functions were normal. Both parents and 5 of the siblings (3 boys and 2 girls) were heterozygous for the variant. They did not show any clinical or laboratory signs of small vessel disease.ConclusionsCOL4A1 has previously been associated with dominant small vessel disease of the brain and other organs, manifesting with high penetrance in heterozygous mutation carriers. Our findings provide evidence that COL4A1-related encephalopathy can be inherited in an autosomal recessive manner, which is important for counseling, prognosis, and treatment. Genotype-phenotype correlations remain to be established.