Muscle Shortening and Spastic Cocontraction in Gastrocnemius Medialis and Peroneus Longus in Very Young Hemiparetic Children.

OBJECTIVES: Muscle shortening and spastic cocontraction in ankle plantar flexors may alter gait since early childhood in cerebral palsy (CP). We evaluated gastrosoleus complex (GSC) length, and gastrocnemius medialis (GM) and peroneus longus (PL) activity during swing phase, in very young hemiparetic children with equinovalgus. METHODS: This was an observational, retrospective, and monocentric outpatient study in a pediatric hospital. Ten very young hemiparetic children (age 3 ± 1 yrs) were enrolled. These CP children were assessed for muscle extensibility (Tardieu scale XV1) in GSC (angle of arrest during slow-speed passive ankle dorsiflexion with the knee extended) and monitored for GM and PL electromyography (EMG) during the swing phase of gait. The swing phase was divided into three periods (T1, T2, and T3), in which we measured a cocontraction index (CCI), ratio of the Root Mean Square EMG (RMS-EMG) from each muscle during that period to the peak 500 ms RMS-EMG obtained from voluntary plantar flexion during standing on tiptoes (from several 5-second series, the highest RMS value was computed over 500 ms around the peak). RESULTS: On the paretic side: (i) the mean XV1-GSC was 100° (8°) (median (SD)) versus 106° (3°) on the nonparetic side (p = 0.032, Mann-Whitney); (ii) XV1-GSC diminished with age between ages of 2 and 5 (Spearman, ρ = 0.019); (iii) CCIGM and CCIPL during swing phase were higher than on the nonparetic side (CCIGM, 0.32 (0.20) versus 0.15 (0.09), p < 0.01; CCIPL, 0.52 (0.30) versus 0.24 (0.17), p < 0.01), with an early difference significant for PL from T1 (p = 0.03). CONCLUSIONS: In very young hemiparetic children, the paretic GSC may rapidly shorten in the first years of life. GM and PL cocontraction during swing phase are excessive, which contributes to dynamic equinovalgus. Muscle extensibility (XV1) may have to be monitored and preserved in the first years of life in children with CP. Additional measurements of cocontraction may further help target treatments with botulinum toxin, especially in peroneus longus.

Five-step clinical assessment in spastic paresis.

Among the three main factors of motor impairment that emerge in chronological order following a lesion to central motor pathways, the last two antagonize movement: 1) stretch-sensitive paresis, a reduction of agonist motor unit recruitment upon voluntary command, worsened by antagonist stretch; 2) soft tissue contracture, and 3) muscle overactivity. Types of muscle overactivity include 1) spasticity, an increase in the velocity-dependent response to muscle stretch, measured at rest; 2) spastic dystonia, i.e., chronic tonic muscle activity at rest, sensitive to stretch of the dystonic muscle and 3) spastic co-contraction, an inappropriate degree of antagonistic contraction during voluntary agonist command, sensitive to stretch of the co-contracting muscle. A five-step clinical assessment may closely parallel this phenomenology, in which the first four steps aim at quantifying the antagonistic potential of each muscle group. Step-1 measures passive range of motion, i.e., the angle of arrest upon slow stretch of the muscle group assessed (minimizing spastic dystonia), which provides insight on soft tissue length and extensibility. Step-2 measures the angle of catch or clonus upon fast passive stretch of the muscle group assessed, which provides insight on stretch reflex excitability. Step-3 measures the range of active motion against the muscle group assessed, a net result of agonist recruitment minus the combined resistance from passive soft tissue stiffness and spastic co-contraction in the muscle group assessed. Step-4 measures the maximal frequency of rapid alternating movements along the maximal active range of motion, evaluating Step-3 performance repeatability. Step-5 evaluates active function, using for example a walking test (10 m or 2 min) for lower limb and the Modified Frenchay Scale for upper limb assessment, and perceived function through patient global subjective assessment.

Does somatosensory loss induce adaptation of the gait initiation process?

Gait initiation (GI) is the transient period between posture and movement. Its central programming takes into account the environmental constraints as well as the constraints induced by the body itself. Patients with peripheral sensory neuropathies display a severe proprioceptive deficit leading to balance and gait impairments and rely on a variety of compensatory mechanisms and are known to be dependent on vision. GI was studied on eight healthy subjects and five patients in order to assess the effect of somatosensory loss on the different phases of GI, combined with a manipulation of the visual inputs. Our main hypothesis is that the proprioceptive deficit would induce an adaptation of the GI process, especially when modifying the lower part of peripheral vision. The results show that the pathology induces some adaptations of the GI process, characterized by a decrease of the motor performance (assessed by the maximal anteroposterior velocity of the center of gravity at the end of the first step), a decrease in the spatial parameters (assessed by the peak amplitude of the backward shift of the center of foot pressure during the anticipation phase and the length of the first step), and a non-modification of the temporal parameters (assessed by the duration of the anticipation phase and of the first step). The suppression of the lower part of peripheral vision has no effect on the GI process. The role of the lower part of peripheral vision seems therefore to be less critical for GI, than for balance and locomotion.

How proprioceptive impairments affect quiet standing in patients with multiple sclerosis.

To assess if multiple sclerosis patients with proprioceptive impairment are specifically affected during quiet standing with eyes open and how they can develop motor compensatory processes, 56 patients, classified from sensory clinical tests as ataxo-spastic (MS-AS) or only having spasticity (MS-S), were compared to 23 healthy adults matched for age. The postural strategies were assessed from the centre-of-pressure trajectories (CP), measured from a force platform in the eyes open standing condition for a single trial lasting 51.2 s. The vertical projection of the centre of gravity (CGv) and its vertical difference from the CP (CP-CGv) were then estimated through a biomechanical relationship. These two movements permit the characterization of the postural performance and the horizontal acceleration communicated to the CG and from that, the global energy expenditure, respectively. Both MS-AS and MS-S groups demonstrate larger CGv and CP-CGv movements than healthy individuals of the same age. Whilst similar CGv values are noticed in both MS subgroups, suggesting similar postural performances, statistically significant differences are observed for the CP-CGv component. Biomechanically, this feature expresses the necessity for the MS-AS group to develop augmented neuro-muscular means to control their body movements, as compared to the MS-S group. By demonstrating for both groups of patients similar postural performance accompanied by a varying degree of energy expenditure to maintain undisturbed upright stance, this study reveals that MS-AS patients which are affected by proprioceptive loss can compensate for this deficit with more efficient control strategies, when standing still with their eyes open.

[Role of endoscopy in lymphomatous pathology of the digestive tract]. / Il ruolo dell'endoscopia nella patologia linfomatosa del tubo digerente.

Increasingly frequent reports of lymphoma with a gastro-intestinal primary location have stimulated much interest. Symptomatology has been shown not to be very specific, and scarcely different to that of other gastro-intestinal pathologics, both benign and malignant. The identification of some endoscopic pictures which suggest a lymphomatosic pathology and the possibility of collecting targeted biopsy samples, have placed endoscopy among the most important tests in the diagnostic and staging phase of gastro-intestinal lymphoma. This technique plays an equally important role in the follow-up period, since it allows the therapeutic efficacy of treatment to be assessed and the early identification of possible relapses.

[Therapy of resistant duodenal ulcer]. / Terapia dell'ulcera duodenale resistente.

Significant progress has been made in the treatment of duodenal ulcers since cimetidine went on the market. Furthermore widespread use of the H2 blockers has enable us to identify a group of patients who take 8-12 weeks to heal, despite effective treatment and who are now known as "slow" or non-responders. In tackling the problem of ulcers resistant to medical treatment, the paper details the possibilities offered by current solutions on the basis of personal experience as well as reports in the literature. The results obtainable by surgery are also assessed with emphasis on the identification of suitable patients for and the appropriate timing of his surgical option. Finally a therapeutic flow-chart providing guidelines for the rational selection of therapeutic strategies that still had to be based on uncodified personal preferences is proposed.