Matteo Cioni

Analysis of Ankle Kinetics during Walking in Individuals with Down Syndrome.

The biomechanical characteristics of the ankle during gait of 17 participants with Down syndrome, ages 8 to 36 years, were investigated. Ten volunteers without disabilities of comparable anthropometric parameters were the control group. A 3-dimensional gait analysis was performed using an optoelectronic system equipped with a force platform. Participants with Down syndrome showed significant decreases of plantar-flexor moments and of A1 and A2 joint powers. Furthermore, correlation between kinetic and temporal spatial parameters was markedly reduced or weak in comparison to the control group. These results point out a hypofunctioning of ankle, probably due to hypotonia and ligament laxity.

The pendulum test as a tool to evaluate passive knee stiffness and viscosity of patients with rheumatoid arthritis

BackgroundThe pendulum test of Wartenberg is a technique commonly used to measure passive knee motion with the aim to assess spasticity. We used this test to evaluate changes of the knee angular displacement, passive stiffness and viscosity in rheumatoid arthritis patients. Stiffness and viscosity represent passive resistances to joint motion associated with the structural properties of the joint tissue and of the muscular-tendon complex. Stiffness can be considered an intrinsic property of the tissues to resist deformation, while viscosity is related to cohesive forces between adjacent layers of tissues. Both parameters may influence the joint range of motion affecting angular displacement.MethodsNine women with rheumatoid arthritis were compared with a group of healthy women. With the subject half-lying, the relaxed knee was dropped from near-full extension and the characteristics of the ensuring damped unsustained knee oscillation evaluated. The kinematics of leg oscillations was recorded using ultrasonic markers (Zebris CMS HS 10) and the kinetic data were calculated from kinematic and anthropometric measures.ResultsKnee stiffness significantly increased (p < 0.001) in patients with respect to the control group, while differences in viscosity were not significant. Moreover, the amplitudes of first knee flexion (the maximal flexion excursion after knee release) and first knee extension (the maximal extension excursion after the first knee flexion) were significantly decreased (p < 0.001). A regression analysis showed that disease severity correlated moderately with stiffness (R2 = 0.68) and first flexion (R2 = 0.78). Using a multivariate regression, we found that increasing stiffness was the main factor for the reduction of flexion and extension motions.ConclusionWe showed that the Wartenberg test can be considered a practical tool to measure mechanical changes of knee caused by rheumatoid arthritis. This novel application of Wartenberg test could be useful to follow up the effects of pharmacological and rehabilitative interventions in this disease.

Ovarian LHRH Receptors Increase following Lesions of the Major LHRH Structures in the Rat Brain: Involvement of a Direct Neural Pathway

Specific lesions of different brain structures known to contain or to be coursed by LHRH neurons have been carried out in intact cycling female rats in order to investigate the role played by central LHRH and neuronal systems in the regulation of ovarian and hypophyseal LHRH receptor (LHRH-R) levels, using the stable LHRH analog [D-Ser (TBU)6] Des-Gly10, LHRH ethylamide, buserelin. Radiofrequency lesions were placed bilaterally or unilaterally into female rats showing at least two consecutive estrous cycles, under pentobarbital anesthesia, while groups of animals were sham-operated. Bilateral lesions placed into the septal area and into the nucleus and tract of the diagonal band of Broca (DBB) resulted in a nearly 25-40% stimulation of LHRH binding activity within the ovaries and a 30% inhibition of LHRH analog binding to pituitary homogenate, while lesions placed into the medial preoptic area (MPO), where the majority of LHRH neurons are found, produced a doubling of ovarian LHRH-R accompanied by a 60% decrease of pituitary binding sites. Lesions involving the median eminence and arcuate hypothalamic nucleus, where the most conspicuous convergence of LHRH fibers occurs, produced a twofold increase in ovarian LHRH-R levels and an almost complete loss of pituitary LHRH-R binding capacity, with no change in affinity. In order to clarify the importance of direct neural signals modulating the ovarian LHRH-R concentration, lesions were placed in the right or left MPO and DBB, and the content of LHRH-R measured in right and left ovaries. Lesions placed unilaterally (right or left) produced a significant increase of LHRH-R binding activity within the ovary ipsilateral to the lesion, while a reduction or no effect was observed in the contralateral gland. Data show a marked stimulation of ovarian LHRH-R number following bilateral lesions placed in the major LHRH-containing structures, while pituitary LHRH binding sites are significantly inhibited, indicating impairment in the rate and/or amplitude of endogenous hypothalamic LHRH release. Furthermore results obtained following unilateral lesions indicate that a neural mechanism is involved in ovarian LHRH receptor induction and further reinforce our view that a direct neural connection links the brain and the ovaries.

Neuroendocrineimmunology (NEI) at the turn of the century: towards a molecular understanding of basic mechanisms and implications for reproductive physiopathology

The interactions between the nervous, endocrine and immune systems require a complex communication network. The central nervous system (CNS) affects the immune system through endocrine, paracrine and neuronal mechanisms. Evidence that this bidirectional communication plays a vital role in the regulation of physiological homeostatic mechanisms while a disfunction of the neuroendocrineimmune balance favors the susceptibility to a number of diseases is derived largely by animal models but also by an increasing number of clinical studies in different fields, including endocrinology, reproductive physiology, pediatrics, oncology, neurology and psychiatry. An increasing number of endocrine hormones, neurotransmitters and neuropeptides are expressed in immune tissues and cells and are actively involved in the physiological regulation of immunity. Conversely, the endocrine and nervous systems harbor receptors for a wide variety of immunologically-derived substances, suggesting potential regulatory feedback loops between the three major integrative bodily systems. Major implications for the reproductive endocrinology field are that psychoneuroendocrine processes may alter fertility via immunomodulation, and that events that occur as part of immune responses influence the neuroendocrine axes, which in turn counter-regulate immune function. In the present article, some features of reproductive-immune interactions will be described, and the neuroendocrineimmune dialogue via the chief reproductive hormone, luteinizing hormone-releasing hormone (LHRH), will be summarized as prototype of intersystem crosstalk. A particular emphasis will be given to the cytokine-LHRH interrelationships both at central (i.e. especially with the astroglial compartment) and peripheral levels. The surprisingly similar communication network systems used by the gonads and the thymus will be summarized, and the sexually-driven dimorphisms dictating female versus male reproductive and immunological capacities reviewed. Evidence that neural, endocrine and immune systems work together as a single unit are emphasized in animal models and human pathologies where interruption of NEI feedback loops results in long lasting pathological consequences for the nervous, endocrine and immune functions.

Opposite Changes of Pituitary and Ovarian Receptors for LHRH in Ageing Rats: Further Evidence for a Direct Neural Control of Ovarian LHRH Receptor Activity

Hypophyseal and ovarian receptors for the neurohormone LHRH (LHRH-R) have been measured in young (3-4 months), middle-aged (8-11 months), constant estrous (CE, 10-14 months) and pseudopregnant (PR, 16-18 months) rats in order to study whether changes in hypothalamic and/or peripheral LHRH-like peptide production might precede and/or accompany the onset of reproductive failure observed in aging rats. Furthermore, we have investigated whether the neural efferent system from the brain to the ovary is affected with aging. The pattern of pituitary LHRH-R modifications during the estrous cycle of middle-aged rats shows lower LHRH-R levels on the second day of diestrus, resulting in a shift of the maximal LHRH binding capacity in the morning of proestrus. On the other hand, when comparing pituitary LHRH-R of animals exhibiting constant vaginal cornification (CVC) or repetitive PP with young estrus rats, no significant difference could be observed. Young rats responded to electrical stimulation (ES) of the medial preoptic area with an acute elevation of LHRH-R while ES performed in CVC, or PP animals resulted in a significant increase of hypophyseal LHRH binding capacity similar to the one observed in young estrous controls, indicating an impairment in the neural signals impinging in the pulse generating system, in old rats, and not an intrinsic defect of the LHRH-R per se. Ovarian LHRH-R concentration is higher in middle-aged cycling animals on the day of vaginal proestrus, compared to levels measured in young animals at any phase of the estrous cycle. Similarly, CE rats displaying CVC as well as PP animals show significantly higher numbers of LHRH-R with no change in affinity, than young estrus rats. CVC and PP rats receiving unilaterally an intraovarian injection of the potent LHRH antagonist, Ac-D-Cl-Phe1,2, D-Trp3, D-Phe6, D-Ala10, LHRH, showed an acute drop of LHRH-R measured within the treated ovary with no significant changes taking place in the vehicle-treated contralateral gland, suggesting that changes of endogenous ovarian LHRH-like peptide might participate in the mechanism(s) responsible for LHRH receptor increase observed in aging rats. In order to investigate the participation of a direct neural efferent pathway in ovarian LHRH-R regulation, young and old rats were subjected to spinal cord transection (above T10-T11). Bilateral transection of the spinal cord in young animals in the morning of proestrous markedly increased ovarian LHRH-R concentration in the afternoon (17.00 h) of the same day.(ABSTRACT TRUNCATED AT 400 WORDS)

Infant Neurological Examination from 3 to 12 Months : Predictive Value of the Single Items

The prognostic value of the single items of a standardised neurological examination, the Hammersmith Infant Neurologic Examination (HINE), was explored longitudinally in 658 infants at 3, 6, 9 and 12 months post-term age. ROC curves were built based on the presence/absence of cerebral palsy at 2 years of age. Global HINE scores showed very high prediction (ROC curve areas above 0.9) at all ages. The items with the highest predictive value were always movement quality and quantity. In the first semester, among the most predictive items were those assessing tone, while beyond that time they were reflexes and reactions. Our results show that the high predictive value of the HINE across the first year of life is granted by the successful combination of different groups of items for each age-period. This should be recognised in clinical practice when assessing the significance of individual neurological profiles.

Spectrum of gross motor and cognitive functions in children with cerebral palsy: Gender differences

BACKGROUND Multiple differences between males and females are reported both in physiological and pathophysiological conditions. AIMS To test the hypothesis that gender could influence the motor and cognitive development in children with cerebral palsy (CP). METHODS Prospective, cross-sectional. One hundred seventy one children with CP (98 males and 73 females) were evaluated for motor (Gross Motor Function Measure, Gross Motor Function Classification System) and cognitive (Bayley II, Wechsler Scales) functions. Eighty-four of them were assessed before and other eighty-seven children after 4 years of age. RESULTS No gender-related differences were observed in children with diplegia or quadriplegia, both for motor and cognitive functions. On the contrary, females with hemiplegia scored significantly better (P < 0.01) in cognitive functions and in the dimension D (standing) of the Gross Motor Function Measure, under the age of 4 years. These differences were not observed after this age. CONCLUSIONS In this study we point out that gender might influence differently the psycho-motor development of children with hemiplegia and of those with a more severe clinical involvement as diplegia and quadriplegia.

Functional assessments of the knee joint biomechanics by using pendulum test in adults with Down syndrome

In this study, we assessed kinematics and viscoelastic features of knee joint in adults with Down syndrome (DS) by means of the Wartenberg pendulum test. This test allows the measuring of the kinematics of the knee joint during passive pendular motion of leg under the influence of gravity. In addition, by a combination of kinematic and anthropometric data, pendulum test provides estimates of joint viscoelastic properties by computing damping and stiffness coefficients. To monitor the occurrences of muscle activation, the surface electromyogram (EMG) of muscle rectus femoris was recorded. The experimental protocol was performed in a group of 10 adults with DS compared with 10 control adults without DS. Joint motion amplitude, velocity, and acceleration of the leg during the first knee flexion significantly decreased in persons with DS with respect to those without DS. This behavior was associated with the activation of rectus femoris in subjects with DS that resulted in increasing of joint resistance shortly after the onset of the first leg flexion. The EMG bursts mostly occurred between 50 and 150 ms from the leg flexion onset. During the remaining cycles of pendular motion, persons with DS exhibited passive leg oscillations with low tonic EMG activity and reduced damping coefficient compared with control subjects. These results suggest that adults with DS might perform preprogrammed contractions to increase joint resistance and compensate for inherent joint instability occurring for quick and unpredictable perturbations. The reduction of damping coefficients observed during passive oscillations could be a predictor of muscle hypotonia.

Learning Upright Standing on a Multiaxial Balance Board

Upright stance on a balance board is a skill requiring complex rearrangement of the postural control. Despite the large use of these boards in training the standing posture, a comprehensive analysis of the learning process underlying the control of these devices is lacking. In this paper learning to maintain a stable stance on a multiaxial oscillating board was studied by analyzing performance changes over short and long periods. Healthy participants were asked to keep the board orientation as horizontal as possible for 20 sec, performing two sessions of 8 trials separated by 15-min pause. Memory consolidation was tested one week later. Amplitude and variability of the oscillations around horizontal plane and area and sway path of the board displacement decreased rapidly over the first session. The performance was stable during the second session, and retained after 1 week. A similar behavior was observed in the anterior-posterior and medial-lateral directions for amplitude and variability parameters, with less stable balance in the anterior-posterior direction. Approximate entropy and mean power frequency, assessing temporal dynamics and frequency content of oscillations, changed only in the anterior-posterior direction during the retention test. Overall, the ability to stand on a balance board is rapidly acquired, and retained for long time. The asymmetric stability between anterior-posterior and medial-lateral directions replicates a structure observed in other standing stances, suggesting a possible transfer from previous postural experiences. Conversely, changes in the temporal dynamics and the frequency content could be associated with new postural strategies developed later during memory consolidation.

Physiological Electromyographic Activation Patterns of Trunk Muscles During Walking

It is well known that, in spite of its crucial role in the posture, locomotion and voluntary movements, trunk has received less consideration from researchers than upper and lower limbs. On the other hand, rehabilitative interventions of patients with upper motoneuron syndrome have always been focused firstly on treatment and recovery of trunks posture during standing, sitting and walking. Trunk is a complex anatomical structure and it is composed by a large variety of bones, articulations, ligaments and muscles. From a functional point of view, trunk muscles have been subdivided into two systems: a local system which ensures stability and a global system which enables movements. Muscles of these two systems work by eccentric and concentric contractions, according to the functional needs. Surprisingly, in the literature are reported only a few studies regarding the trunk muscle activations during walking. These studies investigated the electromyographic activation patterns in different experimental conditions as walking on a walkway, over a treadmill at different velocities, in water or in deep-water. Furthermore, data analysis was differently performed by analyzing the qualitative and quantitative features of timing and amplitude of electromyographic recordings for each muscle or by other more sophisticated methods as cluster analysis or principal components analysis. Finally, some variability has been observed in the normal population also including sex differences. The aim of this review is to show the state of art of this topic, in normal subjects.