Longitudinal study in patients with myotonic dystrophy type 1: correlation of brain MRI abnormalities with cognitive performances.

PURPOSE: Myotonic dystrophy type 1 (DM1) is a muscular dystrophy with neurological, cognitive, and radiological abnormalities. The developmental or degenerative nature of these abnormalities, and their progression over time, remains unclear. The aim of this study is to perform a longitudinal assessment of imaging and cognitive performances in a group of patients with DM1. METHODS: A longitudinal observational study was conducted in a group of 33 DM1 patients. All patients underwent cognitive and MRI evaluation, including the use of structural and diffusion tensor imaging techniques, at baseline and follow-up evaluation (4 years). Longitudinal changes in white matter lesion (WML), volumetric analysis, and diffusivity values were assessed and correlated with neuropsychological test findings. RESULTS: An increase in WML was observed in 16 patients (48.5%). An increase in ventricular system volume and a decrease in volume of the left thalamus, caudates, putamen, and hippocampus were observed (p < 0.001). Global cortical volume showed a significant decrease (p < 0.001), although no changes were observed in white matter volume. A significant increase in mean diffusivity and decrease in fractional anisotropy for the white matter were found (p < 0.001). Neuropsychological evaluation showed a significant deterioration in test performance that measures working memory (Letter-Number Sequencing, p = 0.049) and visuospatial skills (Benton Visual Retention Test, p = 0.001). These findings were significantly associated with WML load (working memory p = 0.002 and visuospatial skills p = 0.021) and mean diffusivity increase (visuospatial skills p = 0.003 in the corpus callosum and working memory p = 0.043 in the right cerebral white matter). CONCLUSION: White matter and grey matter involvement in DM1 patients is progressive. Patients experience a worsening in cognitive impairment that correlates with white matter involvement. These findings support the neurodegenerative nature of this disease.

Sprint mechanics evaluation using inertial sensor-based technology: A laboratory validation study.

Advances in micro-electromechanical systems have turned magnetic inertial measurement units (MIMUs) into a suitable tool for vertical jumping biomechanical evaluation. Thus, this study aimed to determine whether appropriate reliability and agreement reports could also be obtained when analyzing 20-m sprint mechanics. Four bouts of 20-m sprints were evaluated to determine whether the data provided by a MIMU placed at the lumbar spine could reliably assess sprint mechanics and to examine the validity of the MIMU sensor compared to force plate recordings. Maximal power (P0 ), force (F0 ), and velocity (V0 ), as well as other mechanical determinants of sprint performance associated with the force-velocity, power-velocity, and ratio of forces-velocity, such as applied horizontal force loss (Sfv ) and decrease in ratio of forces (Drf ), were calculated and compared between instrumentations. Extremely large-to-very large correlation levels between MIMU sensor-based sprint mechanics variables and force plate recordings were obtained (mean±SD, force plate vs MIMU; V0, 8.61±0.85 vs 8.42±0.69; F0 , 383±110 vs 391±103; P0 , 873±246 vs 799±241; Sfv, -44.6±12.7 vs -46.2±10.7), ranging from 0.88 to 0.94, except for Drf, which showed weak-to-moderate correlation level (r=.45; -6.32±1.08 vs -5.76±0.68). Step-averaged force values measured with both systems were highly correlated (r=.88), with a regression slope close to the identity (1.01). Bland and Altman graphical representation showed a no random distribution of measured force values. Finally, very large-to-extremely large retest correlation coefficients were found for the intertrial reliability of MIMU measurements of sprint performance variables (r value ranging from .72 to .96). Therefore, MIMUs showed appropriate validity and reliability values for 20-m sprint performance variables.

Brain Involvement in Myotonic Dystrophy Type 1: A Morphometric and Diffusion Tensor Imaging Study with Neuropsychological Correlation.

OBJECTIVE: Myotonic dystrophy type 1 (DM1), the most prevalent inherited neuromuscular disease in adults, is a genetic multisystem disorder with a well-established but not well-characterized cerebral involvement. The aim of this study was to evaluate the presence of white matter and gray matter abnormalities in DM1 patients and to investigate their relationship with neurocognitive dysfunction. METHODS: A total of 42 DM1 patients and 42 healthy controls were included in the study. Clinical, cognitive, and magnetic resonance imaging evaluations, including the use of structural and diffusion tensor imaging (DTI) techniques, were performed. White matter lesion (WML) load, volumetric analysis, and diffusivity changes were assessed and correlated with clinical and neuropsychological test findings. RESULTS: WMLs were significantly more frequent in DM1 patients (p < .001), and anterior temporal lobe lesions were only found in the patient group. Global and regional cortical volume loss and corpus callosum atrophy were found. Diffuse white matter DTI abnormalities, including fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity were observed with sparing of the internal capsule. Subcortical structures showed volume loss and increased median diffusivity. Neuropsychological evaluation showed significant impairment in several cognitive functions, but only visuospatial impairment was correlated with white matter abnormalities and cortical atrophy. Daytime sleepiness was associated with WML and ventral diencephalon and pallidum volume loss. CONCLUSION: DM1 produces a widespread involvement of white matter and gray matter, including cortical and subcortical structures. These structural abnormalities are involved in the progressive neuropsychological functional impairment in these patients.

Frailty assessment based on wavelet analysis during quiet standing balance test.

BACKGROUND: A standard phenotype of frailty was independently associated with an increased risk of adverse outcomes including comorbidity, disability and with increased risks of subsequent falls and fractures. Postural control deficit measurement during quiet standing has been often used to assess balance and fall risk in elderly frail population. Real time human motion tracking is an accurate, inexpensive and portable system to obtain kinematic and kinetic measurements. The aim of this study was to examine orientation and acceleration signals from a tri-axial inertial magnetic sensor during quiet standing balance tests using the wavelet transform in a frail, a prefail and a healthy population. METHODS: Fourteen subjects from a frail population (79±4 years), eighteen subjects from a prefrail population (80±3 years) and twenty four subjects from a healthy population (40±3 years) volunteered to participate in this study. All signals were analyzed using time-frequency information based on wavelet decomposition and principal component analysis. FINDINGS: The absolute sum of the coefficients of the wavelet details corresponding to the high frequencies component of orientation and acceleration signals were associated with frail syndrome. INTERPRETATION: These parameters could be of great interest in clinical settings and improved rehabilitation therapies and in methods for identifying elderly population with frail syndrome.

Wavelet analysis based on time-frequency information discriminate chronic ankle instability.

BACKGROUND: Ankle sprains are one of the most common lower extremity injuries. Real time human motion tracking is an accurate, inexpensive and portable system to obtain kinematic and kinetic measurements. The purpose of this study was to discriminate between subjects with chronic ankle instability and subjects with stable ankles through inertial tracking technology and force plates. METHODS: Twelve subjects (mean (SD) 23.16 (5.32) years, 174.83 (8.78) cm, 73.58 (17.10) kg) with stable ankles and 13 (mean (SD) 24.69 (5.91) years, 173.31 (9.07) cm, 69.61 (15.32) kg) with chronic ankle instability performed the Star Excursion Balance Test. Time-frequency information based on wavelet decomposition was used for analysing all signals. FINDINGS: Dynamic balance impairment associated with chronic ankle instability was observed in the peak amplitude in the wavelet approximation as well as the absolute sum of the coefficients of the wavelet details of the acceleration, orientation and force signals. These results were found despite Star Excursion Balance Test performance during anterior, posteromedial and posterolateral excursions lead to similar specific reach distances in both limbs in either the chronic ankle instability or stable ankle groups. INTERPRETATION: These parameters could be of great interest in detecting dynamic balance impairment in individuals at risk of sprains that might otherwise go undetected by only reach distance assessment.

Evaluation of spatial resolution of a PET scanner through the simulation and experimental measurement of the recovery coefficient.

PURPOSE: In order to measure spatial resolution of a PET tomograph in clinical conditions, this study describes and validates a method based on the recovery coefficient, a factor required to compensate underestimation in measured radioactivity concentration for small structures. METHODS: In a PET image, the recovery factors of radioactive spheres were measured and their comparison with simulated recovery coefficients yielded the tomographic spatial resolution. Following this methodology, resolution was determined in different surrounding media and several conditions for reconstruction, including clinical conditions for brain PET studies. All spatial resolution values were compared with those obtained using classical methods with point and line sources. RESULTS: In each considered condition, spatial resolution of the PET image estimated using the recovery coefficient showed good agreement with classical methods measurements, validating the procedure. CONCLUSION: Measurement of the recovery coefficient provides an assessment of tomographic spatial resolution, particularly in clinical studies conditions.

Transferencia de los dedos del pie a la mano en una amputación total de los dedos: a propósito de un caso / Transfer of toe to fingers in total finger amputation of one hand: a case report

La mano catastrófica es aquella que ha sufridouna lesión compleja con pérdida de tejido y deteriorofuncional importante. La amputación de varios dedos deuna mano ocasiona importantes limitaciones para la fuerzade prensión y la pinza. En el caso de manos catastróficas enlas que no es posible el reimplante de dedos, una buenaopción terapéutica es la transferencia de dedos del pie a lamano.Presentamos un caso de amputación traumática de loscinco dedos de la mano izquierda a nivel de las articulacionesmetacarpofalángicas.Se realizó una transferencia en una primera cirugía delprimer dedo del pie izquierdo a la posición de primer dedode la mano izquierda y en una segunda cirugía una transferenciadel segundo y tercer dedo del pie derecho a laposición de cuarto y quinto dedo de la mano izquierda. Elpaciente, a los cuatro meses de la cirugía, presenta una manofuncional y útil para las actividades de la vida diaria. Realiza lapinza y tiene sensibilidad en el pulpejo del primer dedo que lepermite discriminar dos puntos separados a 1,5 cm(AU)

The catastrophic hand is one with severeinjury with loss of tissue and significant functional impairment.Amputation of several fingers of one hand results insignificant limitations to the grip and pinch strength. In theevent of a catastrophic hand in which it is not possible toreimplant fingers, a good therapeutic option is the transferof toes to the hand.We report a case of traumatic amputation of the fivefingers of the left hand at the joints metacarpal.In the first surgery, first toe is transferred from his leftfoot to position of first finger of his left hand and in a secondsurgery it is transferred second and third toe right footto position fourth and fifth finger left hand. The patient afterfour months from the surgery has a functional hand foractivities of daily life. Patient performs grip and pinch andhas sensibility in pulp of first finger that allows discriminatingtwo points separated 1.5 cm(AU)