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Changes of right-hemispheric activation after constraint-induced, intensive language action therapy in chronic aphasia: fMRI evidence from auditory semantic processing.

Mohr B, Difrancesco S, Harrington K, Evans S, Pulvermüller F - Front Hum Neurosci (2014)

Bottom Line: All patients demonstrated significant clinical improvements of language functions after therapy.This activation increase was stronger for highly ambiguous sentences than for unambiguous ones.These results suggest that the known language improvements brought about by intensive constraint-induced language action therapy at least in part relies on circuits within the right-hemispheric homologs of left-perisylvian language areas, which are most strongly activated in the processing of semantically complex language.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, Charité Universitätsmedizin, Campus Benjamin Franklin Berlin, Germany.

ABSTRACT
The role of the two hemispheres in the neurorehabilitation of language is still under dispute. This study explored the changes in language-evoked brain activation over a 2-week treatment interval with intensive constraint induced aphasia therapy (CIAT), which is also called intensive language action therapy (ILAT). Functional magnetic resonance imaging (fMRI) was used to assess brain activation in perilesional left hemispheric and in homotopic right hemispheric areas during passive listening to high and low-ambiguity sentences and non-speech control stimuli in chronic non-fluent aphasia patients. All patients demonstrated significant clinical improvements of language functions after therapy. In an event-related fMRI experiment, a significant increase of BOLD signal was manifest in right inferior frontal and temporal areas. This activation increase was stronger for highly ambiguous sentences than for unambiguous ones. These results suggest that the known language improvements brought about by intensive constraint-induced language action therapy at least in part relies on circuits within the right-hemispheric homologs of left-perisylvian language areas, which are most strongly activated in the processing of semantically complex language.

No MeSH data available.


Related in: MedlinePlus

BOLD ambiguity contrast (high vs. low ambiguity sentences) in the left and right hemisphere (LH, RH) before and after therapy (pre, post). As the relative activation is plotted, negative bars mean that unambiguous sentences led to stronger brain activation than the more complex ambiguous ones. This was the case before therapy in the right hemisphere. After therapy, this RH under-activation to semantically ambiguous sentences disappeared (significant interaction of the factors Prepost × Hemisphere, p < 0.034).
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Figure 6: BOLD ambiguity contrast (high vs. low ambiguity sentences) in the left and right hemisphere (LH, RH) before and after therapy (pre, post). As the relative activation is plotted, negative bars mean that unambiguous sentences led to stronger brain activation than the more complex ambiguous ones. This was the case before therapy in the right hemisphere. After therapy, this RH under-activation to semantically ambiguous sentences disappeared (significant interaction of the factors Prepost × Hemisphere, p < 0.034).

Mentions: A 2 × 2 × 2 (ROI × Hemisphere × Session) repeated measures ANOVA documented a significant two-way interaction between the factors scanning Session and Hemisphere [F(1, 5) = 8.349, p = 0.034] revealing a significant change in activation in the RH in the post-therapy session compared to the pre-treatment session, but no change in the left hemisphere across the two sessions (see Figure 6). Before therapy, right hemispheric activation was significantly stronger for unambiguous sentences than for ambiguous ones, but after therapy, this difference had disappeared. Please recall that healthy controls had shown stronger activation for ambiguous sentences than for unambiguous ones in these same ROIs; the reverse effect in our patients was therefore surprising. In this context the vanishing of unambiguous sentence-superiority in the RH of aphasic patients over therapy can be seen as a step toward typical brain activation. We will discuss this result in more detail below.


Changes of right-hemispheric activation after constraint-induced, intensive language action therapy in chronic aphasia: fMRI evidence from auditory semantic processing.

Mohr B, Difrancesco S, Harrington K, Evans S, Pulvermüller F - Front Hum Neurosci (2014)

BOLD ambiguity contrast (high vs. low ambiguity sentences) in the left and right hemisphere (LH, RH) before and after therapy (pre, post). As the relative activation is plotted, negative bars mean that unambiguous sentences led to stronger brain activation than the more complex ambiguous ones. This was the case before therapy in the right hemisphere. After therapy, this RH under-activation to semantically ambiguous sentences disappeared (significant interaction of the factors Prepost × Hemisphere, p < 0.034).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231973&req=5

Figure 6: BOLD ambiguity contrast (high vs. low ambiguity sentences) in the left and right hemisphere (LH, RH) before and after therapy (pre, post). As the relative activation is plotted, negative bars mean that unambiguous sentences led to stronger brain activation than the more complex ambiguous ones. This was the case before therapy in the right hemisphere. After therapy, this RH under-activation to semantically ambiguous sentences disappeared (significant interaction of the factors Prepost × Hemisphere, p < 0.034).
Mentions: A 2 × 2 × 2 (ROI × Hemisphere × Session) repeated measures ANOVA documented a significant two-way interaction between the factors scanning Session and Hemisphere [F(1, 5) = 8.349, p = 0.034] revealing a significant change in activation in the RH in the post-therapy session compared to the pre-treatment session, but no change in the left hemisphere across the two sessions (see Figure 6). Before therapy, right hemispheric activation was significantly stronger for unambiguous sentences than for ambiguous ones, but after therapy, this difference had disappeared. Please recall that healthy controls had shown stronger activation for ambiguous sentences than for unambiguous ones in these same ROIs; the reverse effect in our patients was therefore surprising. In this context the vanishing of unambiguous sentence-superiority in the RH of aphasic patients over therapy can be seen as a step toward typical brain activation. We will discuss this result in more detail below.

Bottom Line: All patients demonstrated significant clinical improvements of language functions after therapy.This activation increase was stronger for highly ambiguous sentences than for unambiguous ones.These results suggest that the known language improvements brought about by intensive constraint-induced language action therapy at least in part relies on circuits within the right-hemispheric homologs of left-perisylvian language areas, which are most strongly activated in the processing of semantically complex language.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, Charité Universitätsmedizin, Campus Benjamin Franklin Berlin, Germany.

ABSTRACT
The role of the two hemispheres in the neurorehabilitation of language is still under dispute. This study explored the changes in language-evoked brain activation over a 2-week treatment interval with intensive constraint induced aphasia therapy (CIAT), which is also called intensive language action therapy (ILAT). Functional magnetic resonance imaging (fMRI) was used to assess brain activation in perilesional left hemispheric and in homotopic right hemispheric areas during passive listening to high and low-ambiguity sentences and non-speech control stimuli in chronic non-fluent aphasia patients. All patients demonstrated significant clinical improvements of language functions after therapy. In an event-related fMRI experiment, a significant increase of BOLD signal was manifest in right inferior frontal and temporal areas. This activation increase was stronger for highly ambiguous sentences than for unambiguous ones. These results suggest that the known language improvements brought about by intensive constraint-induced language action therapy at least in part relies on circuits within the right-hemispheric homologs of left-perisylvian language areas, which are most strongly activated in the processing of semantically complex language.

No MeSH data available.


Related in: MedlinePlus