Types of Neuroplasticity and Factors Affecting Language Recovery in Patients with Aphasia: A Systematic Review

Introduction: Aphasia is an acquired language injury apart from cognitive, motor, or sensory damages, as the result of a brain injury and stroke in the left hemisphere. In the acute phase of aphasia (the first two or three months) a preponderance of people show certain degrees of recovery, the neural mechanisms of which are yet to be detected, other than the fact that it is related to the plasticity changes in the patient's brain. Neuroplasticity is the capacity of a brain to change or be modified at cellular or behavioral levels. Objectives: The current study aimed at reviewing the literature on neuroplasticity and factors affecting language recovery of patients with aphasia. Data Sources: PubMed, Google Scholar, ScienceDirect, Irandoc, Magiran, SID, Web of Knowledge, Ovid, Springer, and manual search of reference lists from January1990 to April 2o17. Inclusion Criteria: Neuroplasticityand aphasia keywords in the title of the article, studies conducted only on human samples, and adult samples with acquired aphasia. Results: Out of the 6637 retrieved studies, eight articles met the inclusion and exclusion criteria and two related papers were further reported. Recent studies show that three types of changes, in the nervous activity following stroke are closely related to aphasia recovery: reactivation of the injured areas of the left hemisphere or perilesional left hemisphere regions regarding language assignments, the ability to process language in the right hemisphere, and compensatory activity of the right hemisphere, which can hinder language recovery. Conclusions: Most studies demonstrated that areas around the left hemisphere lesion engage in the recovery of the language; certain studies, on the other hand, reported that areas around the right hemisphere are involved, and some consider both hemispheres to be involved in the language recovery. It is difficult to predict the improvement of language owing to the involvement of various factors. Limitations: One of the most important limitations was the unavailability of the full-text of three articles.