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Results for “sensorimotor function”

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PubMed1998

Neuropsychological analysis of the visuomotor problems in children born preterm at < or = 32 weeks of gestation: a 5-year prospective follow-up.

Forty-six intellectually normal children born preterm (< or =32 weeks of gestation) without major neurological disabilities and a control group of term children matched for age, sex, and parental educational and occupational status were assessed at the age of 5 years using neuropsychological tests emphasizing perceptual and visuomotor functions. The results show that in terms of cognitive functions these preterm children are a very heterogenous group, but many of them still have problems in visuospatial and sensorimotor functions. The preterm children achieved lower mean scores in tests where coordination and voluntary control of hands in combination with tactile, kinaesthetic, and visuospatial perception were needed. They had most difficulty with drawing directions of lines and in integrating two or more forms. They also had problems with 3-dimensional constructions as well as visual perception of rotated shapes or slopes of lines.

Child, Preschool↗

PubMed2000

Artificial sensorimotor integration in spinal cord injured subjects through neuromuscular and electrotactile stimulation.

Spinal cord injured (SCI) subjects lack sensorimotor functions. Neuromuscular electrical stimulation (NMES) systems have been used to artificially restore motor functions, but without proprioceptive feedback, SCI subjects can control NMES systems only when they can see their limbs. In a gait restoration system, the subject looks down to the ground to be aware of where his foot is while in a grasping activity, maximum grip strength is employed regardless of the force that is required to perform tasks. This report focuses on artificial sensorimotor integration. Multichannel stimulation was used to restore motor functions while encoded tactile sensation (moving fused phantom images) relating to artificially generated movements was provided by electrotactile stimulation during walking and grasping activities. The results showed that the sensorimotor integration attained yielded both the recognition of artificial grasp force patterns and a technique to be used by paraplegics allowing spatial awareness of their limb while walking.

Adult↗

PubMed2003

Somatosensory and motor disturbances in patients with parietal lobe lesions.

Lesion studies show that a wide range of integrative sensorimotor functions can be selectively disturbed in patients with parietal lobe damage. Lesions restricted to the somatosensory representations on the anterior parietal lobe produce somatosensory deficits that resemble deafferentated states, including the secondary effects on motor control. Slightly more posterior lesions often are associated with impairment of more complex synthetic somatosensory functions similar to those observed after dorsal column lesions. Damage of the posterior parietal lobe can selectively interfere with virtually every aspect of somatosensory function. These perceptive and cognitive disturbances may or may not be associated with complex motor disturbances of the apractic type. The frequent association of astereognosia and tactile apraxia illustrate the mutual interdependence of the sensorimotor processes involved in active touch and the proximity of the respective processing modules. Parietal lobe function is critical for the control of force and posture, and for the formation of the body image and its relation to external space (the guidance of movements, including the eyes, to external objects). Imaging studies underscore the prominent role of the parietal cortex as a sensorimotor interface and provide complementary information about the interrelationship between perception and action. Action observation activates premotor cortex, but parietal cortex is also recruited whenever an action involves objects, thus emphasizing the significance of parietal cortex for object-directed motor behavior. In contrast to the ventral-dorsal route processing dichotomy in the visual system, both the perceptual-cognitive and motor aspects of somatosensory processing are compromised after parietal damage, demonstrating a different functional architecture of the two sensory systems. The preservation of the comprehension of the meaning of gestures or of object use in patients with lesions restricted to the parietal lobe reveals that the semantic aspects of motor behavior are mediated in the temporal lobe.

Animals↗

PubMed1990

A region in the dorsolateral striatum of the rat exhibiting single-unit correlations with specific locomotor limb movements.

1. To examine the activity of single units in the lateral striatum of the awake rat with respect to sensorimotor function, 788 units were recorded during locomotion and passive testing. The focus of this report is on 138 units (18%) that fired in relation to sensorimotor activity of a single limb. The remaining units were related to other body parts (16%), to general body movement (38%), or were unresponsive (28%). 2. Firing rates of limb-related units were near zero during resting behavior but increased markedly during treadmill locomotion. Each of the 138 units exhibited a rhythmic pattern of discharge in phase with the locomotor step cycle. Passive testing revealed that 86/97 units tested (89%) responded to passive manipulation of a single limb, exhibiting increased firing rates. Of these, 77 (90%) were related to contralateral and 9 (10%) to ipsilateral limbs. Sixty-one units (71%) were related to a forelimb and 25 (29%) to a hindlimb. Of the 86 units responding to passive manipulation. 34/48 units tested (71%) also responded to cutaneous stimulation of the same limb but no other part of the body. 3. To study in greater detail the rhythmic unit discharges in phase with the locomotor step cycle, computer-synchronized videotape recordings were used to generate perimovement time histograms constructed around discrete locomotor movements of each limb (n = 17 units). Activity of each unit was shown to be restricted to a specific portion of a particular limb's step cycle. The majority of units discharged throughout (8 units) or during a portion of (3 units) the swing phase, whereas other units fired during a portion of stance (3 units), footfall (2 units), or foot off (1 unit). 1. The specificity of unit firing was further demonstrated by the finding that rhythmic discharges, related to discrete locomotor limb movements in the forward direction, were completely absent during spontaneous deviations such as backward or disrupted locomotion. 5. Units related to limb movement were located in the far lateral, especially the dorsolateral, subregion of the striatum. This subregion extend rostrocaudally from A-P +1.6 to -1.0 mm relative to bregma. No clear somatotopic organization was observed, but this issue requires further study. 6. These results show that functional representations of individual limbs can be demonstrated in the lateral striatum of the rat, within a subregion containing terminals of projections from somatic sensorimotor cortex.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1991

Dysphagia in patients with the post-polio syndrome.

BACKGROUND AND METHODS: Dysphagia may develop in some patients many years after an attack of acute paralytic poliomyelitis. To identify clinical or subclinical signs of oropharyngeal dysfunction, we examined 32 patients (mean age, 48.9 years) with the post-polio syndrome (defined by new weakness in the limbs). Of the 32 patients, 14 had symptoms of new swallowing difficulties, and 18 were asymptomatic in this respect; 12 had a history of bulbar involvement during acute poliomyelitis. Swallowing function was assessed objectively by ultrasonography, videofluoroscopy, and an oral motor index score for 10 components of oral function. RESULTS: All but 1 of the 32 patients, regardless of whether they had new symptoms or previous bulbar involvement, had some abnormality on detailed testing of oropharyngeal function; only 2 patients had any signs of aspiration. The mean oral motor index score (a quantitative measure of oral sensorimotor function) in the patients was higher than that in age-matched normal subjects (P less than 0.001). Videofluoroscopy showed abnormalities of varying severity, including unilateral bolus transport through the pharynx, pooling in the valleculae or pyriform sinuses, delayed pharyngeal constriction, and impaired tongue movements. On ultrasonography, the mean (+/- SD) duration of wet swallows was significantly longer in the symptomatic patients than in the asymptomatic patients (2.67 +/- 0.70 vs. 1.65 +/- 0.42 seconds). The four patients who were reexamined two years later had objective signs of worsening oropharyngeal function and corresponding new symptoms. CONCLUSIONS: In patients with the post-polio syndrome, the bulbar muscles often have clinical or subclinical signs of dysfunction. These abnormalities suggest that in bulbar neurons there is a slowly progressive deterioration similar to that in the muscles of the limbs.

Adult↗

PubMed2005

Beyond the reward hypothesis: alternative functions of nucleus accumbens dopamine.

According to the dopamine (DA) hypothesis of reward, DA systems in the brain, particularly in the nucleus accumbens, are thought to directly mediate the rewarding or primary motivational characteristics of natural stimuli such as food, water and sex, as well as various drugs of abuse. However, there are numerous problems associated with this hypothesis. Interference with accumbens DA transmission does not substantially blunt primary motivation for natural rewards such as food, but it does disrupt the propensity of animals to engage in effortful responding to obtain food. Electrophysiological and voltammetric studies indicate that novel stimuli, conditioned stimuli that predict reward, and instrumental behaviors that deliver natural rewards all act to stimulate DA activity. Accumbens DA acts as a modulator of several functions related to motivated behavior, and can influence normal and pathological cognitive function, activational aspects of motivation, anergia or psychomotor slowing in depression, the impact of conditioned stimuli, plasticity and a variety of sensorimotor functions.

Animals↗

PubMed2001

Functional abdominal pain in the elderly.

Although aging per se affects function throughout the gut, particularly after age 70, the observed changes are relatively modest and often asymptomatic, perhaps because of the vast reserve of neuromuscular functional elements in the gut. The proximal esophagus, anus, and pelvic floor are possible exceptions to this generalization, and the combination of aging and factors such as minor strokes or obstetric damage often results in dysphagia, constipation, or fecal incontinence. Managing elderly patients with functional abdominal pain demands clinical acumen, tact, understanding, and patience. Further studies are required to elucidate the consequences of aging on gastrointestinal sensorimotor function at several levels of the digestive tract. With the expected explosion in the proportion of the population older than age 75, this field should become a high priority for clinical and research efforts. Also required will be a major campaign to educate patients and practitioners and multidisciplinary collaborations among primary care practitioners, gastroenterologists, psychologists, and physiatrists to provide optimal pain management in the elderly.

Abdominal Pain↗

PubMed2006

Local fluorouracil chemotherapy interferes with neural and behavioral recovery after brain tumor-like mass compression.

In this study, we investigated the impact of intracerebral delivery of chemotherapy on functional recovery from focal cortical tissue displacement, characteristic of brain tumors. Unilateral focal brain compression was induced by epidural implantation of an inverted hemisphere-shaped bead over the sensorimotor cortex. Microinjections of a total of 1mg chemoagent fluorouracil or the same volume of saline were made into the compressed cortex. Behavioral tests of forelimb sensorimotor function were conducted during 4 weeks' observation. Rats subjected to any of the three types of lesions, saline microinjection plus cortical compression, chemoagent microinjection alone, or chemoagent microinjection combined with cortical compression, demonstrated significant behavioral deficits in several sensorimotor tasks, compared with saline-microinjected control animals. In placing tests, behavioral deficits elicited by each single treatment were worsened by combined treatment with chemoagent microinjection and focal cortical compression. Concurrently, local delivery of chemoagent into the compressed cortex induced increased cortical tissue loss, necrosis and apoptosis. These data indicate that local chemotherapy exacerbates compression-induced neurological impairment, and a model of controlled focal cortical compression may provide a valuable means to improve anti-cancer therapeutic designs with reduced deterioration of brain function.

Animals↗

PubMed1995

Functional mapping of the sensorimotor cortex: combined use of magnetoencephalography, functional MRI, and motor evoked potentials.

Combined use of magnetoencephalography (MEG), functional magnetic resonance imaging (f-MRI), and motor evoked potentials (MEPs) was carried out on one patient in an attempt to localise precisely a structural lesion to the central sulcus. A small cyst in the right frontoparietal region was thought to be the cause of generalised seizures in an otherwise asymptomatic woman. First the primary sensory cortex was identified with magnetic source imaging (MSI) of somatosensory evoked magnetic fields using MEG and MRI. Second, the motor area of the hand was identified using f-MRI during hand-squeezing. Then transcranial magnetic stimulation localised the hand motor area on the scalp, which was mapped onto the MRI. There was a good agreement between MSI, f-MRI and MEP as to the location of the sensorimotor cortex and its relationship to the lesion. Multimodality mapping techniques may thus prove useful in the precise localisation of cortical lesions, and in the preoperative determination of the best treatment for peri-rolandic lesions.

Adult↗

PubMed2001

The parietal lobe as a sensorimotor interface: a perspective from clinical and neuroimaging data.

Lesion studies show a wide range of sensorimotor functions that can be selectively disturbed in patients with parietal lobe damage. This is illustrated by the selective impairment of unimodal or polymodal sensorimotor transformations in patients with apraxia. These clinically apparent deficits of goal-directed motor behavior are complimented by more subtle sensorimotor transformation disorders such as mirror agnosia and ataxia that can only be disclosed by special tests. Imaging studies further exemplify the prominent role of the parietal cortex as a sensorimotor interface and provide new information about the interrelationship between perception and action. Action observation activates premotor cortex, but parietal cortex is also recruited whenever an action involves objects. This emphasizes the significance of parietal cortex for goal-directed motor behavior. The intact comprehension of the meaning of gestures or of tool use shows the preservation of the cognitive aspects of motor behavior as long as lesions are restricted to the parietal lobe.

Apraxia, Ideomotor↗

PubMed2004

Methods for the experimental functional assessment of rat sciatic nerve regeneration.

In experimental peripheral nerve studies, the rat sciatic nerve model is widely used to examine functional changes after different surgical repairs or pharmacological treatments, following nerve injury. The number and diversity of tests which have been used to assess functional recovery after experimental interventions often makes it difficult to recommend any particular indicator of nerve regeneration. Functional assessment after sciatic nerve lesion has long been focused on walking track analysis, therefore, this article describes in more detail the method to obtain and measure the walking tracks in order to calculate the sciatic functional index (SFI). However, it is important to note that the validity of the SFI has been questioned by several researchers. In addition, the present review includes other traditional tests described in the experimental peripheral nerve literature regarding the rate of return of motor function and sensation, such as the extensor postural thrust (EPT), nociceptive function, and the gastrocnemius-soleus weight parameters. In the last decade, several authors have designed a series of sensitive quantitative methods to assess the recovery of hind limb locomotor function using computerized rat gait analysis. This study aims to review kinematic measures that can be gathered with this technology, including calculation of sciatic functional index, gait-stance duration, ankle kinematics and toe out angle (TOA). A combination of tests, each examining particular components of recovered sensorimotor function is recommended for an overall assessment of rat sciatic nerve regeneration.

Animals↗

PubMed1993

Somatosensory evoked potentials in patients with cerebral hemorrhage and infarct. Correlation with CT, clinical data and their prognostic significance on limb function.

Somatosensory evoked potentials (SEP) arising from median nerve stimulation were recorded in 102 patients with unilateral cerebral hemorrhage or infarct located in basal ganglion, internal capsule, thalamus or cerebral lobe. Of them 42 cases were followed up and reexamined with SEPs. Three types of SEPs were observed: 1) absence of all SEPs components, 39 cases; 2) slight to moderate abnormalities of SEPs, 37 cases; 3) symmetric and normal SEPs, 26 cases. The total abnormal rate of SEPs was 76.5%. There were no definite correlations between abnormal SEPs and lesion location, size and lesion nature. The diagnosis of cerebral vascular disease might be obtained more directly and precisely by CT scan than by SEPs. However, SEPs may serve as an objective neurophysiologic means in assessing the neurological function of the affected limb, in which their abnormalities and severity are of great value to evaluate the probability and the degree of sensorimotor functional rehabilitation of the limb. When SEPs are absent, the recovery of the limb functions may be very poor no matter whether it is hemorrhage or infarct regardless of its lesion size and location.

Adult↗

PubMed2003

New insights on sensorimotor integration: from hand action to speech perception.

In the last two decades the integrative role of the frontal premotor cortex (a mosaic of agranular/disgranular areas lying in front of the primary motor cortex) have been more and more elucidated. Among its various functions, sensorimotor transformation, and action representation storage, also for nonstrictly motor purposes, are the most intriguing properties of this region, as shown by several researches. In this article we will mainly focus on the ventro-rostral part of the monkey premotor cortex (area F5) in which visual information describing objects and others' acting hands are associated with goal-directed motor representations of hand movements. We will describe the main characteristics of F5 premotor neurons and we will provide evidence in favor of a parallelism between monkeys and humans on the basis of new experimental observations. Finally, we will present some data indicating that, both in humans and in monkeys, action-related sensorimotor transformations are not restricted to visual information but concern also acoustic information.

Functional Laterality↗

PubMed1990

Animal models of cerebral stroke: pharmacological protection of function.

We used a photochemical technique which induces thrombotic infarction by intravenous injection of the fluorescein derivative Rose Bengal and focal illumination of the intact skull surface. Following such photochemically induced infarcts in the sensorimotor neocortex of rats, posttreatment with flunarizine, a class IV calcium antagonist, within a critical period of the first 6 h after infarction, results in marked sparing of sensorimotor function (tactile/proprioceptive limb placing reactions), while animals remain normoglycemic and are free of drug-induced behavioral toxicity. This could reflect flunarizine-induced coping of neuronal tissue with ischemia-related ionic shifts. It is argued that photochemical thrombosis and middle cerebral artery occlusion can fruitfully complement each other as experimental stroke models.

Animals↗

PubMed2006

Noise-enhanced balance control in patients with diabetes and patients with stroke.

OBJECTIVE: Somatosensory function declines with diabetic neuropathy and often with stroke, resulting in diminished motor performance. Recently, it has been shown that input noise can enhance human sensorimotor function. The goal of this study was to investigate whether subsensory mechanical noise applied to the soles of the feet via vibrating insoles can be used to improve quiet-standing balance control in 15 patients with diabetic neuropathy and 15 patients with stroke. Sway data of 12 healthy elderly subjects from a previous study on vibrating insoles were added for comparison. METHODS: Five traditional sway parameters and three sway parameters from random-walk analysis were computed for each trial (no noise or noise). RESULTS: Application of noise resulted in a statistically significant reduction in each of the eight sway parameters in the subjects with diabetic neuropathy, the subjects with stroke, and the elderly subjects. We also found that higher levels of baseline postural sway in sensory-impaired individuals was correlated with greater improvements in balance control with input noise. INTERPRETATION: This work indicates that noise-based devices could ameliorate diabetic and stroke impairments in balance control.

Adult↗

PubMed2005

Rapid functional recovery after spinal cord injury in young rats.

Responses to traumatic injury in the immature spinal cord may be different from those in adults. We modified an adult model of weight-drop injury to characterize the histopathology and functional recovery after spinal cord injury (SCI) in rat pups at postnatal day 14-15. A 10-g weight was dropped from 2.5 or 5.0 cm at T8-T9. Hindlimb function was evaluated at 24 h and 1, 2, 3, and 4 weeks after injury using the Combined Behavioral Score that estimates overall hind limb sensorimotor function, and the BBB scale for open field locomotion. Histopathology was examined at 15 min, 24 h, and 4 weeks after SCI. The initial hemorrhagic lesion was similar to that seen in adults, but the time course of secondary loss of ventral horn motor neurons was extended. By 4 weeks, only a partial rim of white matter surrounding a central cavity was seen. The 5.0 cm injury group exhibited significantly less recovery of function at 4 weeks than the 2.5 cm group. In the latter, the degree of hindlimb deficit at 4 weeks was similar to that previously described for adults with 10 g x 2.5 cm SCI. However, pups in both injury groups exhibited a significantly faster rate of recovery than adults. Recovery was maximal by 1 week after SCI in pups as compared to 3-4 weeks in adults. The more rapid functional recovery observed in the pups suggests that this new model may be useful for studying mechanisms of functional plasticity after SCI.

Age Factors↗

PubMed1993

Liquid stool incontinence with severe urgency: anorectal function and effective biofeedback treatment.

The motor and sensory function of the anorectum is well characterised in patients with solid stool incontinence. Fewer data are available in the case of liquid stool incontinence. Anorectal sensorimotor function was studied in 16 patients with liquid stool incontinence and severe urgency (10 with diarrhoea) unresponsive to conventional medical treatment, and in 16 healthy volunteers. The only significant difference found between incontinent patients and controls was a reduction in squeeze duration (p < 0.0001). Fourteen patients were selected to receive biofeedback treatment. Treatment was associated with a substantial improvement in continence in 12 patients and with a significant decrease in urgency (p < 0.05). Bowel frequency was not significantly influenced. Most patients showed a persistent improvement in anal motor function. Functional parameters were not predictive of outcome of treatment; the poor responders showed major psychological problems. In conclusion, an anal motor deficit is often present in disabling liquid stool incontinence. Biofeedback may improve anal continence in 75% of patients.

Adult↗

PubMedDate not supplied

Medical and social factors affecting behaviour patterns in patients with acquired brain damage: a study of patients living at home three years after the incident.

This study aimed to describe the consequence of stroke or brain trauma 3 years after the incident for individuals living at home, and how patterns of behaviour were influenced by determinants. One hundred and eighty-eight individuals in three age groups answered a questionnaire. Answers were classified according to WHO's ICIDH, and 11 areas of behaviour were distinguished. Diagnoses and locations of lesions were noted from medical records. Impairment and disability increased with increasing age at the time of the incident. Individuals working before but not after the incident indicated decreased life satisfaction and changed intellectual function, personal care, and domestic/housework/gardening activities, and inability to organize their time. Those who had resumed work but at different tasks indicated changed emotional and sensorimotor function and content in leisure activities. The influence of the localization and lateralization of the lesion is also discussed.

Activities of Daily Living↗