Early Aphasia Rehabilitation Is Associated With Functional Reactivation of the Left Inferior Frontal Gyrus

Abstract

A n important issue for language rehabilitation after stroke is the relationship between the effects of therapeutic interventions and the functional changes observed in brain language-related areas. Most studies focused on the spontaneous recovery of language, [1][2][3][4][5][6][7] but only a few, often single case descriptions, focused on patients submitted to language rehabilitation. [8][9][10][11][12][13] All of these were conducted on chronic patients. The rate of complete spontaneous (ie, without language therapy) aphasia recovery poststroke has been estimated at ≈33% in the first month, 43% after 4 months, and 50% 12 months later.14 However, the concept of spontaneous recovery of language may not be appropriate (as human beings are extensively exposed to language). The term language therapy commonly relates to formal interventions provided by speech therapists aimed at improving different language abilities with specific exercises.Evidence supports the use of language rehabilitation in stroke, particularly if intensively administered for short courses in chronic aphasics. 15,16 In a pilot study, Godecke et al 17 found that daily aphasia therapy in early stroke, that is, mean 3 days poststroke (dps), resulted in improved communication outcomes in moderate to severe aphasia. Brain plasticity induced by language training has not been extensively investigated to date. Several studies, conducted in chronic patients, suggested that functional correlates of aphasia recovery could be either the activation of predominantly left hemisphere (LH) language-related areas [18][19][20][21][22] or of the homologous right hemisphere (RH) areas, 2,23-25 but often the authors do not clarify whether patients were formally treated and to what extent, or not. Saur et al 4 suggest that in the postacute stages of recovery (2 weeks poststroke), the LH areas would be reduced in activation, whereas after months Background and Purpose-Early poststroke aphasia rehabilitation effects and their functional MRI (fMRI) correlates were investigated in a pilot, controlled longitudinal study. Methods-Twelve patients with mild/moderate aphasia (8 Broca, 3 anomic, and 1 Wernicke) were randomly assigned to daily language rehabilitation for 2 weeks (starting 2.2 [mean] days poststroke) or no rehabilitation. The Aachen Aphasia Test and fMRI recorded during an auditory comprehension task were performed at 3 time intervals: mean 2.2 (T1), 16.2 (T2), and 190 (T3) days poststroke. Results-Groups did not differ in terms of age, education, aphasia severity, lesions volume, baseline fMRI activations, and in task performance during fMRI across examinations. Rehabilitated patients significantly improved in naming and written language tasks (P<0.05) compared with no rehabilitation group both at T2 and T3. Functional activity at T1 was reduced in language-related cortical areas (right and left inferior frontal gyrus and middle temporal gyrus, right inferior parietal lobule and superior temporal gyrus) in patients compared with controls. T2 and T3 follow-ups r...

Using functional imaging to understand therapeutic effects in poststroke aphasia

“…To avoid this problem Mattioli et al designed a small group study with a control group who received no therapy [4]. The therapy started very early, just two days post-stroke, so it is perhaps not surprising that overall recovery attributable to therapy (5%) was smaller than in the control group (10%), although still significantly greater for naming and writing skills.…”

“…Mattioli [4]  Well-designed study (both in terms of therapy and functional neuroimaging outcomes), although with a rather small number of patients. They show that it is possible to capture therapy effects in the acute phase and found a nice correlation in spared left IFG between therapy effects and inscanner task.…”

Optimal timing of speech and language therapy for aphasia after stroke: more evidence needed

“…Recently, several trials have been published on the efficacy of early initiated SLT for post-stroke aphasia [14,15,17,18,[56][57][58]. None of these studies directly compared early with later initiated SLT and they vary in the way recovery was measured (using percentages of maximum recovery, correcting for baseline data or using absolute data).…”

Aphasia therapy early after stroke: behavioural and neurophysiological changes in the acute and post-acute phases

“…However, up to now it is still not possible to disentangle with certainty the effects of language therapy from the effects of spontaneous recovery in the acute stage of stroke (Pulvermüller & Berthier, 2008). Although a growing number of studies indicate the efficacy of aphasia therapy early after stroke (Brady et al, 2012;Godecke et al, 2012;Mattioli et al, 2014), two studies have recently postulated that language intervention early after stroke, in the acute and post-acute stage of aphasia, may not be beneficial (Bowen et al, 2012) or even not recommended (Laska et al, 2011). A possible explanation for the lack of therapy success in these studies might be the low intensity (maximum of 3 hr and 45 min per week) and the use of functional outcome measures rather than impairmentspecific measures.…”

“…An important characteristic of neurons is the ability to form new connections and the more frequent neurons are active simultaneously, the stronger their connections become (Hebbian learning) (Kleim & Jones, 2008;Pulvermüller & Berthier, 2008). By increasing the intensity of impairment-based treatment, enhancement of neuronal connections can be achieved in the preferred left hemispheric lesional and perilesional areas in both the acute and chronic stage of stroke, and this has been related to a favourable outcome (Belin et al, 1996;Davis & Harrington, 2006;Fridriksson, Richardson, Fillmore, & Cai, 2012;Léger et al, 2002;Mattioli et al, 2014;Meinzer et al, 2004;Rochon et al, 2010).…”