Bimanual Gesture Imitation in Alzheimer's Disease.

BACKGROUND/OBJECTIVE: Unimanual gesture production or imitation has often been studied in Alzheimer's disease (AD) during apraxia testing. In the present study, it was hypothesized that bimanual motor tasks may be a sensitive method to detect impairments of motor cognition in AD due to increased demands on the cognitive system. METHODS: We investigated bimanual, meaningless gesture imitation in 45 AD outpatients, 38 subjects with mild cognitive impairment (MCI), and 50 normal controls (NC) attending a memory clinic. Participants performed neuropsychological background testing and three tasks: the Interlocking Finger Test (ILF), Imitation of Alternating Hand Movements (AHM), and Bimanual Rhythm Tapping (BRT). RESULTS: The tasks were short and easy to administer. Inter-rater reliability was high across all three tests. AD patients performed significantly poorer than NC and MCI participants; a deficit to imitate bimanual gestures was rarely found in MCI and NC participants. Sensitivity to detect AD ranged from 0.5 and 0.7, specificity beyond 0.9. ROC analyses revealed good diagnostic accuracy (0.77 to 0.92). Impairment to imitate bimanual gestures was mainly predicted by diagnosis and disease severity. CONCLUSION: Our findings suggest that an impairment to imitate bimanual, meaningless gestures is a valid disease marker of mild to moderate AD and can easily be assessed in memory clinic settings. Based on our preliminary findings, it appears to be a separate impairment which can be distinguished from other cognitive deficits.

Using static and dynamic canonical correlation coefficients as quantitative EEG markers for Alzheimer's disease severity.

We analyzed the relation between Alzheimer's disease (AD) severity as measured by Mini-Mental State Examination (MMSE) scores and quantitative electroencephalographic (qEEG) markers that were derived from canonical correlation analysis. This allowed an investigation of EEG synchrony between groups of EEG channels. In this study, we applied the data from 79 participants in the multi-centric cohort study PRODEM-Austria with probable AD. Following a homogeneous protocol, the EEG was recorded both in resting state and during a cognitive task. A quadratic regression model was used to describe the relation between MMSE and the qEEG synchrony markers. This relation was most significant in the δ and θ frequency bands in resting state, and between left-hemispheric central, temporal and parietal channel groups during the cognitive task. Here, the MMSE explained up to 40% of the qEEG marker's variation. QEEG markers showed an ambiguous trend, i.e. an increase of EEG synchrony in the initial stage of AD (MMSE>20) and a decrease in later stages. This effect could be caused by compensatory brain mechanisms. We conclude that the proposed qEEG markers are closely related to AD severity. Despite the ambiguous trend and the resulting diagnostic ambiguity, the qEEG markers could provide aid in the diagnostics of early-stage AD.

Evaluación clínica de la oseointegración de implantes con plasma rico en plaquetas y hueso liofilizado en pacientes con perdida dentoalveolar por trauma en el sector anterior: primera fase / Clinical evaluation of implant osseointegration with platelet rich plasma and lyophilizated bone in patients with dento alveolar loss due to trauma in the anterior area: first phase

Introducción: el propósito del presente estudio (primera fase) fue evaluar clínica y radiográficamente la oseointegración de implantes con regeneración ósea por medio de plasma rico en plaquetas (PRP) y hueso liofilizado, colocados en pacientes con pérdida dentoalveolar por trauma en el sector anterior, durante las primeras etapas de cicatrización de tejidos blandos; atendidos en el Hospital Universitario San Vicente de Paúl (HUSVP) de la ciudad de Medellín, Colombia. Métodos: se colocaron quince implantes en seis pacientes que sufrieron pérdida dental por trauma en la zona anterior superior e inferior. La colocación de los implantes se realizó entre los ocho a veinte días posteriores al trauma, los cuales se dejaron sumergidos cuatro meses en la mandíbula y seis meses en el maxilar superior. En la segunda fase quirúrgica se realizó una evaluación clínica y radiográfica para determinar la oseointegración. Resultados: el porcentaje de oseointegración fue 93,3% (catorce implantes). Un implante falló (6,7%) y presentó movilidad sin signos de infección o radiolucidez en la radiografía periapical, lo que sugiere que la falla pudo ocurrir por poca cantidad ósea o trauma quirúrgico. Conclusión: el presente estudio mostró que el porcentaje de oseointegración en pacientes con trauma dentoalveolar fue bueno con la utilización del PRP según el protocolo utilizado.

Introduction: the aim of the present study was to evaluate clinically and radiographically the osseointegration of implants with bone regeneration by platelet rich plasma (PRP) and freeze-dried bone, placed in patients with dentoalveolar loss by trauma in the anterior region, during the firsts stages of soft tissue healing, treated at the Hospital Universitario San Vicente de Paúl (Medellín-Colombia). Methods: 15 implants were placed in six patients who suffered tooth loss due to trauma in the anterior maxillary and mandible area. The placement of the implants was performed between eight to twenty days after trauma, and they were submerged four months in the mandible and six months in the maxilla. A clinical and radiographic evaluation was done at the second-stage surgery to determine osseointegration. Results: osseointegration percentage was 93.3% (14 implants). An implant failed (6.7%) and showed mobility without any infection signs or radiolucency, which suggests that failure, could be the result of surgical trauma. Conclusion: the present study showed that osseointegration percentage in patients with dentoalveolar trauma was good with the utilization of PRP according to the present protocol.

Medidor de las presiones ejercidas por los tejidos blandos intraorales en posición de reposo sobre las estructuras dentarias / evice for the measurement intra-oral soft tissue pressures on dental structures during rest. Key words: Device for pressure measurment, soft tissues, orthodontics

El objetivo de este trabajo fue diseñar unaparato que sirva en un futuro para realizarestudios que ayuden a esclarecer los factoresetiológicos ambientales (hábitos, aparatosortodonticos) e intrínsecos (componenteanterior de fuerzas -CAF-, reducción de lalongitud del arco con la edad, presión ejercidapor la erupción de los terceros molares, factoresidiopáticos y fuerzas originadas por el ligamentoperiodontal) que influyen en la posición dental.Para lograr este objetivo se modificó yperfeccionó el manómetro inclinado diseñadopor Jimenez y cols, en 1990.Como no se obtuvieron resultados confiables se decidió entonces experimentar con otro tipo de aparato. Del manómetro inclinado se continuo utilizando el sistema intraoral de medición con vejigas, dispositivo que se mejoro haciéndolo suficientemente delgado, confiable, fácil de manipular e intercambiable de paciente a paciente...

Neuronal activity of submucosal plexus of pyloric and ileocecal sphincteric regions of the cat gastrointestinal tract.

Extracellular recording of neuronal activity of the submucosal plexus of isolated pyloric and ileocecal sphincteric regions of cat intestine revealed both spontaneously active and silent neurons. The spontaneously active neurons consisted of fast- and slow-burst-type units and single-spike units. The silent neurons generated trains of spikes in response to deformation of the ganglion by the recording electrode or in response to local application of acetylcholine (Ach, 6 X 10(-5) -6 X 10(-2) microM/l) on the ganglion surface. Interactions of the excitatory type were made manifest by the synchronous activity of cells in the forms of a "driver-follower" interaction. Even more complex interactions of an excitatory and inhibitory character were observed when the beginning of discharge of one neuron caused activation of another which was followed by a pause as in the first neuron discharge. Analysis of the obtained data indicated a qualitative similarity of the neuronal organization of the submucosal plexus along the entire length of the alimentary canal. It is concluded that neurons of the plexus in sphincteric regions are interconnected in a single functional ensemble. However, the results of the study show that silent cells and single-spike neurons predominate and are located mainly at the mesenteric border and in the central band of the segment. This is evidently a reflection of the functional significance of the sphincters which prevent reflux within the alimentary canal.

[Neuronal activity of the submucous plexus of the pyloric and ileocecal sphincters]. / Neironal'naia aktivnost' podslizistogo spleteniia piloricheskogo i ileotsekal'nogo sfinkterov.

In plexus of isolated segments of pyloric and ileo-caecal sphincters of the cat, three types of spontaneously active cells were revealed: 1) with single, 2) with fast, and 3) with slow burst type of discharges, as well as a group of silent neurons only responding to mechanical stimulation with electrode or application of acetylcholine. The data obtained indicated the qualitative unity of neuronal organization of submucous plexus along the alimentary canal, the neurons of the sphincters' plexus included. However, an increasing number of the silent cells and neurons with the single burst activity were revealed in the vicinity of mesenteric border and in the central belt of the segment which, probably, reflected the functional specifics of sphincters.