Regression of Poststroke Aphasia and Concomitant Nonspeech Syndromes Due to Courses of Restorative Therapy Including Intensive Speech Therapy

Objectives. To analyze clinical indicators and fMRI parameters associated with the therapeutic efficacy of courses of complex restorative therapy including intensive speech therapy in various clinical forms and severities of aphasia syndrome. Materials and methods. A total of 40 right-handed patients with aphasia syndrome were studied three months after disease onset before and after courses of therapy (4.7 weeks) including intensive speech therapy (15 h/week). The efficacy of courses of treatment and cognitive rehabilitation was assessed using changes in measures of neuropsychological, neurological, and neuroimaging investigations before and after patients received treatment. The extents of restoration of speech and nonspeech cognitive functions were evaluated (using a 10-point assessment of cognitive functions addressing changes in focal deficit (NIHSS), and patients’ functional recovery (Barthel index, modified Rankin scale). Neuroimaging methods included structural MRI, fMRI at rest, and the fMRI equivalent of the mismatch negativity (MMN) component of event-related potentials using a sequence of standard and deviant sounds (Russian-language phonemes) to obtain the MMN equivalent. A program written in Python 3.6.0 was used. Results. The greatest efficacy of courses of restorative therapy (≥15% improvement on subtests of the quantitative assessment scale) was seen in 28 cases (70%): 18 patients with initially severe and 10 patients with moderate aphasia (independently of the clinical type of aphasia) and in all 11 patients with isolated sensory aphasia. Regression of sensory aphasia was accompanied by marked activation of the intact speech homologs of the right hemisphere and the appearance of a low-volume, low-intensity activation of the left temporal-parietal area, with a near-normal location. Regardless of the clinical form of aphasia, maximum therapeutic efficacy was associated with reorganization of the speech-related resting neural network, including increases in both intrahemisphere and interhemisphere functional connectivity, with increases in intrahemisphere interactions between the posterior speech zones in the left hemisphere on the background of decreases in their interhemisphere connectivity. Statistically significant improvements in motor and sensory functions were seen in nine patients with moderate contralateral spastic hemiparesis (22%) ( p ≤ 0.00), which did not correlate with the level of regression of speech and nonspeech impairments. A minor therapeutic effect was seen in 12 patients (30%) with mild and moderate speech and nonspeech cognitive impairments which did not correlate with any particular clinical form of aphasia. Conclusions. Courses of restorative hospital treatment lasting 4.7 weeks including intensive speech therapy (15 sessions per week) were maximally effective mainly in severe aphasia, as well as in a defined clinical form – isolated sensory aphasia. fMRI data identified a different compensatory reorganization of the neural speech network probably reflecting the features of poststroke neuroplasticity associated with regression of both severe speech impairments and a particular clinical form of aphasia.