The ontogenetic model for CVA rehabilitation with transcranial stimulation

Currently, transcranial stimulation for CVA treatment is based on the interhemispheric rivalry model. This model has proven to have many anomalies, necessitating a new paradigm. Spontaneous recovery from post-CVA hemiplegia has an ontogenetic pattern. We reanalyzed the 2008 longitudinal London study and found that cortical disinhibition is the mechanism for ontogenetic CVA recovery. We propose that transcranial stimulation with 10 Hz rTMS or anode electrical microstimulation can produce CVA recovery similar to spontaneous recovery. (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2466).

Actualmente la aplicación de la estimulación transcraneal para el tratamiento del ACV se realiza con base en el modelo de rivalidad interhemisférica. Este modelo ha mostrado muchas anomalías que hacen necesario un nuevo paradigma. La recuperación espontánea de la hemiplejia post-ACV tiene patrón ontogénico. Reanalizamos el estudio longitudinal de Londres 2008 y encontramos que su propuesta corresponde al mecanismo de recuperación ontogénica del ACV. Planteamos que la estimulación transcraneal, utilizando EMTr a 10 Hz o microestimulación eléctrica anódica, podría recuperar el ACV de manera similar a la recuperación espontánea. (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2466).

Stroke improvement with magnetic stimulation recapitulates ontogeny / Mejoría del ACV con estimulación magnética recapitula la ontogenia

Abstract A patient with chronic brainstem CVA sequelae received one cycle of magnetic stimulation to treat her dysphagia and serendipitously obtained a minimal improvement in her axial movement. Two additional cycles gave her improved postural control and then distal movement, preceded by a display of ipsilateral and contralateral motor evoked potentials, respectively. Magnetic stimulation at 10 Hertz produces cortical disinhibition and reopens the critical neurodevelop ment periods. The ontogenic pattern of hemiplegia recovery in this patient may be explained by an increased and rejuvenated brain plasticity due to critical period reopening through cortical disinhibition. (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2253).

Resumen Una paciente con secuelas crónicas de un ACV del tallo cerebral recibió un ciclo de estimulación magnética para el manejo de la disfagia y, por serendipia obtuvo mejoría leve del movimiento axial. Dos ciclos adicionales le permitieron mejoría del control postural y luego la aparición de movimiento distal, precedidos por la visualización de los potenciales evocados motores ipsilateral y contralateral, respectivamente. La estimulación magnética a 10 Hertz produce desinhibición cortical y reabre los periodos críticos del neurodesarrollo. Es posible, que el patrón ontogénico de recuperación de la hemiplejía en esta paciente se explique por el incremento y rejuvenecimiento de la plasticidad cerebral debido a la reapertura de los periodos críticos, por medio de la desinhibición cortical. (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2253).

Effects of acute mental stress on conditioned pain modulation in temporomandibular disorders patients and healthy individuals

Abstract Stress is a contributing factor to painful temporomandibular disorders (TMD). Nevertheless, the underpinnings of this relationship are not fully understood. Objective To investigate the effects of acute mental stress on conditioned pain modulation (CPM) in TMD patients compared with healthy individuals. Methodology Twenty women with chronic myofascial TMD diagnosed according to the RDC/TMD and 20 age-matched healthy women had the CPM assessed before and after a stressful task using the Paced Auditory Serial Addition Task (PASAT) in a single session. Subjective stress response was assessed with the aid of visual analog scale (VAS). Pressure pain threshold (PPT) on masseter muscle was the test stimulus (TS) and immersion of the participant's hand on hot water was the conditioning stimulus (CS) - CPM-sequential paradigm. Results Healthy individuals reported PASAT are more stressful when compared with TMD patients and the stress task did not affect the CPM in neither group. Nonetheless, a negative correlation was observed between change in CPM and change in TS from baseline to post-stress session, which indicates that the greater the increase in PPT after the stress task, the greater was the decrease in CPM magnitude. The correlation was strong for healthy controls (r=- 0.72, p<0.001) and moderate for TMD patients (r=- 0.44, p=0.047). Conclusions The correlation between the change in CPM and the TS change following the stress task may possibly indicate an overlapping pathway between stress-induced analgesia/hyperalgesia and descending pain inhibition.

Mecanismos de modulación central del dolor: revisión de la literatura / Mechanisms of central pain modulation: literature review

RESUMEN: La percepción del dolor resulta de múltiples y dinámicos mecanismos en el sistema nervioso central (SNC) y periférico que inhiben o facilitan el estímulo y respuesta nociceptiva. Sin embargo, la principal capacidad de modulación esta a cargo del SNC. Los estímulos nociceptivos son detectados por terminaciones nerviosas libres de neuronas periféricas que sinaptan con neuronas aferentes secundarias de la médula espinal. Luego estas fibras decusan para formar las vías nociceptivas ascendentes. Una vez alcanzadas las estructuras subcorticales, se activan las neuronas del tálamo, quienes envían el estímulo hacia la corteza somatosensorial, desencadenando la percepción consciente del dolor y activando el sistema inhibitorio descendente. Para que la modulación nociceptiva se realice, es necesaria la participación de diversas sustancias o neurotransmisores que conectan áreas del SNC especializadas. Por lo tanto, el objetivo de este estudio fue realizar una revisión de la literatura respecto de los mecanismos que participan en los procesos de modulación central del dolor.

SUMMARY: Pain perception results from multiple and dynamic mechanisms in the central nervous system (CNS) and peripheral nervous system that inhibit or facilitate stimulation and nociceptive response. However, neuromodulation is mainly a function of the CNS. Nociceptive stimulus is detected by peripheral neurons receptors that synapse with the secondary afferent neurons of the spinal cord. These fibers cross to conform the ascending nociceptive pathways. Once the subcortical structures are reached, the thalamus`s neurons are activated; the thalamus send the stimulus to the somatosensory cortex, triggering the conscious perception of pain and activating the descending inhibitory system. For the nociceptive modulation to be carried out, the participation of various substances or neurotransmitters that connect specialized CNS areas is necessary. Therefore, the aim of this study was to review the literature regarding the mechanisms involved in central pain modulation processes.

Effects of regional nerve blockade in patients with heart failure / 中国介入心脏病学杂志

Objective To observe the clinical feasibility and effects of regional nerve blockade in patients with heart failure.Methods The study enrolled a total of 10 patients,age range from 55 to 75 years old(average 64?11 years old).The subject includes 8 males and 2 females,among which 6 cases were ischemic cardiomyopathy and 4 cases were dilated cardiomyopathy.All the patients met the criteria of NYHA class Ⅲ-Ⅳ heart function with heavy fluid load unresponsive to optimal medical therapy.Patients with diabetes and renal failure were ruled out from the study.After application of local anesthesia,15 mL of 0.25% Naropin was injected inside Gerota's fascia to achieve regional nerve blockade under CT guidance.Serum and urine electrolytes,neurohormones,renal clearance of sodium and 24-hour urine volume were recorded 24 h before and after the operation.Variartions in heart rate,blood pressure and symptons of dyspnea and edema were also under monitor.Results After nerve blockade,the 24-hour urine volume and renal sodium clearance increased obviously while the level of neurohormones decreased compared with that before operation.No obvious changes in heart rate and blood pressure were recorded and the symptons of heart failure were improved in the patients after operation. No complication was recorded in the study. Conclusion Regional nerve blockade may be a feasible,safe and effective treatment for congestive heart failure patients who do not respond well to the existing optimal medical therapy.