Alessandro Marco De Nunzio

The control of equilibrium in Parkinson's disease patients: Delayed adaptation of balancing strategy to shifts in sensory set during a dynamic task

Processing of sensory information, timing operations and set-shifting can be affected in Parkinsons disease (PD) patients. We investigated their capacity and swiftness to pass from a kinaesthetic- to a vision-dependent behaviour during dynamic balancing on a continuously moving support base. Nineteen on-phase PD patients and 13 age-matched normal subjects stood on a platform continuously translating in the antero-posterior direction at 0.2 Hz. Body segment oscillations were identified by a stereophotogrammetric device and electromyogram (EMG) was recorded from tibialis anterior and soleus. Under constant visual conditions, both patients and normal subjects roughly stabilised head and trunk in space with eyes open (EO) but followed the platform displacement with eyes closed (EC). Amplitude and variability of the periodic EMG bursts were smaller with EO than EC. Constant visual-condition trials were intermingled with trials in which subjects opened (EC-EO) or closed (EO-EC) the eyes in response to an acoustic signal. Both patients and normal subjects changed kinematics and EMG patterns to those appropriate for the new visual condition. However, PD patients were slower in changing their behaviour under the EC-EO condition. These findings show abnormal temporal features in balancing strategy adaptation when shifting from kinaesthetic to visual reference in PD. The delay in the implementation of the vision-dependent behaviour was unexpected, given the advantage vision is supposed to confer to motor performance in PD. This condition may play a major role in the instability of patients performing dynamic postural tasks under changing sensory conditions.

Trunk muscle proprioceptive input assists steering of locomotion

During locomotion, human subjects navigate in their environment and choose the direction by means of the internal representation of space that is continuously updated by sensory input. Aim of this study was to assess whether trunk proprioceptive information plays a role in the definition of the reference frame for orientation. Unilateral trunk muscle vibration was applied during locomotion along a straight path in seven subjects. Vibration was administered either from the onset or in the middle of a seven-step task, under eyes-open (EO) or blindfolded condition. The deviation of the walking trajectory was quantified by the distance of the seventh from the first foot print along the medio-lateral axis. Foot angles and stride lengths were computed for all foot-falls. Vibration produced a clear-cut deviation from the straight-ahead direction when delivered in the middle of blindfolded locomotion. With EO the deviation was much smaller. A mild deviation was obtained in blindfolded condition when vibration started at the onset of locomotion. All deviations from the straight-ahead were accompanied by coherent changes in foot orientation on the ground. Trunk proprioception plays a major role in the definition of locomotor trajectory. Trunk input seems to be weighted against vision and whole-body kinematic information.

Alternate rhythmic vibratory stimulation of trunk muscles affects walking cadence and velocity in Parkinson’s disease

OBJECTIVE During the administration of timed bilateral alternate vibration to homonymous leg or trunk muscles during quiet upright stance, Parkinsonian (PD) patients undergo cyclic antero-posterior and medio-lateral transfers of the centre of foot pressure. This event might be potentially exploited for improving gait in these patients. Here, we tested this hypothesis by applying alternate muscle vibration during walking in PD. METHODS Fifteen patients and 15 healthy subjects walked on an instrumented walkway under four conditions: no vibration (no-Vib), and vibration of tibialis anterior (TA-Vib), soleus (Sol-Vib) and erector spinae (ES-Vib) muscles of both sides. Trains of vibration (internal frequency 100 Hz) were delivered to right and left side at alternating frequency of 10% above preferred step cadence. RESULTS During vibration, stride length, cadence and velocity increased in both patients and healthy subjects, significantly so for ES-Vib. Stance and swing time tended to decrease. Width of support base increased with Sol-Vib or TA-Vib, but was unaffected by ES-Vib. CONCLUSIONS Alternate ES vibration enhances gait velocity in PD. The stronger effect of ES over leg muscle vibration might depend on the relevance of the proprioceptive inflow from the trunk muscles and on the absence of adverse effects on the support base width. SIGNIFICANCE Trunk control is defective in PD. The effect of timed vibratory stimulation on gait suggests the potential use of trunk proprioceptive stimulation for tuning the central pattern generators for locomotion in PD.

Alternate Trains of Postural Muscle Vibration Promote Cyclic Body Displacement in Standing Parkinsonian Patients

Patients suffering from Parkinsons disease (PD) have difficulties with control of stance, postural changes, and walking, seemingly depending on problems in central integration of proprioceptive information. We tested the hypothesis that alternate vibration of postural muscles can induce cyclic medio‐lateral or antero‐posterior sway in PD, mimicking that accompanying body progression during walking, thereby favoring the production of locomotor tasks. In 12 standing PD patients and 11 healthy subjects, we applied trains of vibratory stimuli, bilaterally in an alternating paradigm to soleus, tibialis anterior, or paravertebral muscles. The trains of stimuli were delivered at frequencies selected to be above, near, and below the normal walking rhythm. The displacement of the center of foot pressure (CoP) was recorded. In PD, sway area during unperturbed stance was just larger than in healthy subjects; shifts in CoP in response to vibration were preserved, regardless of the vibrated muscle pair; CoP oscillations along medio‐lateral, but not antero‐posterior direction, were coupled to the vibration trains; time to initiate and terminate the postural responses was normal. PD patients correctly integrate and exploit the vibration‐induced proprioceptive inflow to produce body oscillations comparable to those occurring during walking. Vibratory stimulation can be safely and easily employed to provoke rhythmic postural changes in PD.

Sensori-motor integration during stance: time adaptation of control mechanisms on adding or removing vision.

Sudden addition or removal of visual information can be particularly critical to balance control. The promptness of adaptation of stance control mechanisms is quantified by the latency at which body oscillation and postural muscle activity vary after a shift in visual condition. In the present study, volunteers stood on a force platform with feet parallel or in tandem. Shifts in visual condition were produced by electronic spectacles. Ground reaction force (center of foot pressure, CoP) and EMG of leg postural muscles were acquired, and latency of CoP and EMG changes estimated by t-tests on the averaged traces. Time-to-reach steady-state was estimated by means of an exponential model. On allowing or occluding vision, decrements and increments in CoP position and oscillation occurred within about 2s. These were preceded by changes in muscle activity, regardless of visual-shift direction, foot position or front or rear leg in tandem. These time intervals were longer than simple reaction-time responses. The time course of recovery to steady-state was about 3s, shorter for oscillation than position. The capacity of modifying balance control at very short intervals both during quiet standing and under more critical balance conditions speaks in favor of a necessary coupling between vision, postural reference, and postural muscle activity, and of the swiftness of this sensory reweighing process.

Estimation of human trunk movements by wearable strain sensors and improvement of sensor’s placement on intelligent biomedical clothes

BackgroundThe aim of this study was to evaluate the concept of a wearable device and, specifically: 1) to design and implement analysis procedures to extract clinically relevant information from data recorded using the wearable system; 2) to evaluate the design and placement of the strain sensors.MethodsDifferent kinds of trunk movements performed by a healthy subject were acquired as a comprehensive data set of 639 multivariate time series and off-line analyzed. The space of multivariate signals recorded by the strain sensors was reduced by means of Principal Components Analysis, and compared with the univariate angles contemporaneously measured by an inertial sensor.ResultsVery high correlation between the two kinds of signals showed the usefulness of the garment for the quantification of the movements’ range of motion that caused at least one strain sensor to lengthen or shorten accordingly. The repeatability of signals was also studied. The layout of a next garment prototype was designed, with additional strain sensors placed across the front and hips, able to monitor a wider set of trunk motor tasks.ConclusionsThe proposed technologies and methods would offer a low-cost and unobtrusive approach to trunk motor rehabilitation.

Walking along circular trajectories in Parkinson's disease.

We hypothesized that gait capacities would be more stressed in patients with Parkinsons disease (PD) when walking along curved than straight trajectories, owing to the complex adaptations required for this walking task. Twenty on‐phase patients with PD and 20 healthy subjects walked eyes‐open along straight and curved trajectories for 1 minute at self‐paced cadence and velocity. Step frequency along straight and curved trajectories was computed from video‐recordings of the lower limbs. Step frequency was not affected by trajectory shape in either patients with PD or healthy subjects. Distances run by the patients were shorter than normal under both conditions. However, in PD, distances were relatively shorter during curved than straight walking; therefore, decreased distances in PD were connected with decreased mean step length (as the ratio between distance and step number). No correlation was found between the above mentioned variables and the severity or duration of the disease or the frequency of falls. Walking along curved trajectories can highlight impaired gait control in on‐phase patients with PD, and can be suitable for the routine evaluation of possible walking disorders when straight walking is not significantly affected.

Blood biomarkers role in acute ischemic stroke patients: higher is worse or better?

BackgroundThrombolytic therapy (TT) for acute ischemic stroke (AIS) can provoke bleeding’s complication depending on the ischemic lesion (IL) dimension. Inflammation involved in the setting of acute ischaemic stroke, is associated with infarct size. We aimed to study the independent correlation and association between clinical panel of routinely identified biomarkers, including inflammatory parameters, and cerebral IL dimension and site.ResultsWe evaluated eleven biomarkers in 105 unrelated patients during their hospitalization after acute stroke event. Our data indicate a significant association of: a) confluent IL size with 4th quartile of Erythrocyte Sedimentation Rate (ESR) (OR = 5.250; 95% CI, 1.002 to 27.514) and an independent correlation with sex; b) confluent IL size with 3rd quartile of fibrinogen (OR = 5.5; 95% CI, 1.027 to 29.451); c) confluent IL size with 3rd quartile of platelets (OR= 0.059; 95% CI, 0.003 to 1.175) and independent correlation with sex; d) smaller IL size (OR = 5.25; 95% CI, 1.351 to 20.396) with 3rd quartile of albumin levels and nodular and parenchimal IL size with 2nd (OR = 0.227; 95% CI, 0.053 to 0.981), 3rd (OR = 0.164; 95% CI, 0.038 to 0.711) and 4th (OR = 0.205; 95% CI, 0.048 to 0.870) quartiles albumin levels; e) smaller IL size with 3rd quartile triglycerides (TG) levels (OR = 9; 95% CI, 2.487 to 32.567) and an independent correlation with anterior location. Smaller IL size, anterior AIS turned out to be independently correlated with high serum albumin levels. Finally, high INR and PTT values were associated with worse NIHSS clinical outcomes in contrast to that observed with higher albumin level.ConclusionsWe provide evidence of routine biomarkers levels correlation with acute IL size, independently of age and sex. In addition, we highlight the importance of differentiation of biomarkers normal interval levels for further improvement not only of the clinical decision making but also in post-acute clinical outcome management.

Post-effect of forward and backward locomotion on body orientation in space during quiet stance

Neural circuits responsible for stance control serve other motor tasks as well. We investigated the effect of prior locomotor tasks on stance, hypothesizing that postural post-effects of walking are dependent on walking direction. Subjects walked forward (WF) and backward (WB) on a treadmill. Prior to and after walking they maintained quiet stance. Ground reaction forces and centre of foot pressure (CoP), ankle and hip angles, and trunk inclination were measured during locomotion and stance. In WF compared to WB, joint angle changes were reversed, trunk was more flexed, and movement of CoP along the foot sole during the support phase of walking was opposite. During subsequent standing tasks, WB induced ankle extension, hip flexion, trunk backward leaning; WF induced ankle flexion and hip extension. The body CoP was displaced backward post-WB and forward post-WF. The post-effects are walking-direction dependent, and possibly related to foot-sole stimulation pattern and trunk inclination during walking.

Improving neuro-oncological patients care: basic and practical concepts for nurse specialist in neuro-rehabilitation

BackgroundNeuro-oncological population well expresses the complexity of neurological disability due to the multiple neurological deficits that affect these patients. Moreover, due to the therapeutical opportunities survival times for patients with brain tumor have increased and more of these patients require rehabilitation care. The figure of nurse in the interdisciplinary specialty of neurorehabilitation is not clearly defined, even if their role in this setting is recognized as being critical and is expanding.The purpose of the study is to identify the standard competencies for neurorehabilitation nurses that could be taught by means of a specialization course.MethodsA literature review was conducted with preference given to works published between January 2000 and December 2008 in English. The search strategy identified 523 non-duplicated references of which 271 titles were considered relevant. After reviewing the abstracts, 147 papers were selected and made available to a group of healthcare professionals who were requested to classify them in few conceptual main areas defining the relative topics.ResultsThe following five main areas were identified: clinical aspects of nursing; nursing techniques; nursing methodology; relational and organisational models; legal aspects of nursing. The relative topics were included within each area. As educational method a structured course based on lectures and practical sessions was designed. Also multi-choices questions were developed in order to evaluate the participants’ level of knowledge, while a semi-structured interview was prepared to investigate students’ satisfaction.ConclusionsLiterature shows that the development of rehabilitation depends on the improvement of scientific and practical knowledge of health care professionals. This structured training course could be incorporated into undergraduate nursing education programmes and also be inserted into continuing education programmes for graduate nurses. Developing expertise in neuro-rehabilitation for nurses, will be critical to improve overall care and care management of patients with highly complex disabilities as patients affected by brain tumors. The next step will be to start discussing, at the level of scientific societies linked to the field of neurorehabilitation and oncology, the development of a specialisation course in neurorehabilitation nursing.