Post-activation depression of the lower extremities in stroke patients with spasticity and spastic equinovarus deformity / Depressão pós-ativação das extremidades inferiores de pacientes com acidente vascular cerebral que apresentam espasticidade e deformidade equinovarus por espasticidade

This study aimed to investigate changes of post-activation depression in two groups of patients with or without spastic equinovarus deformity (SED). Paired and independent t-tests were used to compare post-activation depression within and between the groups, respectively. There was a significant positive correlation between diminished post-activation depression and spasticity severity. The soleus and tibialis anterior (TA) post-activation depression values were significantly decreased on the affected sides of patients with SED compared to those without. In patients without SED, the soleus post-activation depression was significantly decreased on the affected side; however, TA post-activation depression was higher on the affected side. Both the soleus and TA become active, but the onset time may be different. The imbalanced muscle tone between the soleus and TA in the early stage after stroke may be related to equinus deformity.

O principal objetivo deste estudo é a investigação da depressão pós-ativação em pacientes com deformidade equinovarus espástica (DEE). Os pacientes foram divididos em dois grupos. Student-t testes pareados e independentes foram utilizados para comparar a depressão pós-ativação intra- e inter-grupos, respectivamente. Houve uma correlação positiva significativa entre a diminuição da depressão pós-ativação e a gravidade da espasticidade. A depressão pós-ativação dos músculos sóleo e tibial anterior (TA) estavam significativamente diminuídas no lado afetado dos pacientes com SEE em relação aos membros sem SEE. Em pacientes sem SEE, a depressão pós-ativação do músculo sóleo encontrava-se significativamente diminuída do lado afetado. No entanto, a depressão pós-ativação do músculo TA era maior no lado afetado que no lado não afetado. Tanto o sóleo quanto o TA serão ativados, mas o tempo para isso pode ser diferente. O desequilíbrio entre o tônus dos músculos sóleo e TA nos estágios iniciais pode estar relacionado à deformidade equina.

Long-term potentiation and long-term depression: a clinical perspective

Long-term potentiation and long-term depression are enduring changes in synaptic strength, induced by specific patterns of synaptic activity, that have received much attention as cellular models of information storage in the central nervous system. Work in a number of brain regions, from the spinal cord to the cerebral cortex, and in many animal species, ranging from invertebrates to humans, has demonstrated a reliable capacity for chemical synapses to undergo lasting changes in efficacy in response to a variety of induction protocols. In addition to their physiological relevance, long-term potentiation and depression may have important clinical applications. A growing insight into the molecular mechanisms underlying these processes, and technological advances in non-invasive manipulation of brain activity, now puts us at the threshold of harnessing long-term potentiation and depression and other forms of synaptic, cellular and circuit plasticity to manipulate synaptic strength in the human nervous system. Drugs may be used to erase or treat pathological synaptic states and non-invasive stimulation devices may be used to artificially induce synaptic plasticity to ameliorate conditions arising from disrupted synaptic drive. These approaches hold promise for the treatment of a variety of neurological conditions, including neuropathic pain, epilepsy, depression, amblyopia, tinnitus and stroke.