Mattioli F, Ambrosi C, Mascaro L, Scarpazza C, Pasquali P, Frugoni M, et al. Early Aphasia Rehabilitation Is Associated With Functional Reactivation of the Left Inferior Frontal Gyrus: A Pilot Study. Stroke. 2013
Functional MRI (fMRI) studies reveal a typical pattern of cortical activation during spontaneous recovery of language following stroke. The acute phase is characterized by reduced activation in the left hemisphere, the subacute phase by activation of bilateral speech areas, and the chronic phase by a shift back to the left hemisphere. These changes correlate with improvement in various aspects of speech production. However, the effects of speech therapy on these activation patterns, particularly in the acute phase, remain unknown.
To address this question, Mattioli and colleagues randomized 12 patients with mild-moderate aphasia to 1 hr per day of speech therapy for 2 wks versus no speech therapy. Therapy was started very early (mean 2.2 days post-stroke). Investigators performed the Aachen aphasia test and fMRI with a language comprehension task at baseline, 2 wks, and 6 months post-stroke. At the 2 wk time point, subjects in the speech therapy group demonstrated improved naming and written language abilities compared to control subjects; this effect persisted at 6 months. In regard to cortical activation, at 2 wks post-stroke only subjects in the speech therapy group showed increased cortical activation in the left inferior frontal gyrus (Broca’s area); the control group subjects had increased activation primarily in the right inferior frontal gyrus (Broca homologue). By 6 month follow-up, both groups demonstrated activation of language areas primarily in the left hemisphere.
This is the first study to explore the effects of aggressive speech therapy in the acute phase post-stroke on cortical activation patterns. The authors nicely demonstrate both the long-term benefit of early speech therapy and a shift in cortical activation toward the left hemisphere as a result of speech therapy. It remains uncertain whether the shift in activation patterns to the right hemisphere in the subacute phase during spontaneous language recovery (seen in this study in control subjects 2 wks post-stroke) is adaptive or maladaptive. Considering that speech therapy group subjects quickly shifted activation back to the left hemisphere and achieved better long-term outcomes, this study may support a maladaptive role for right cortical activation patterns. Perhaps the faster we can promote this left-shift, the better the long-term language function will be. It follows that we may need to get more aggressive with early language therapy for stroke patients. To justify such a change, larger trials are needed comparing different doses and timing of language therapy post-stroke.