Abstract
Title: Verbal encoding fMRI paradigm adds complementary information to cerebral
language lateralization.
Purpose: To explore two conceptually different fMRI paradigms’ ability to lateralize
language.
Methods: A verbal encoding paradigm and a word generation task were performed by
six patients (four right-handed) with therapy-resistant temporal lobe epilepsy (TLE),
and by ten healthy individuals (five right-handed). FMRI laterality indices (LI) and
laterality curves for the anterior cerebral language regions were calculated. Typical
lateralization was defined as left-hemisphere dominance, and a typical as bilateral or
right-hemisphere dominance.
Results: Both paradigms showed predominantly left-sided activation in the anterior
language regions, with typical contralateral cerebellar activity. Thirteen out of sixteen
subjects showed concordant language lateralization results for both paradigms.
Two subjects, both left-handed, showed discordant language lateralization results.
Laterality curves added information for individual subjects with uncharacteristic
results. The verbal encoding task showed overall more widespread activation
compared to the word generation task.
Conclusion: Our results indicate valid language lateralization obtained by the fMRI
verbal encoding paradigm for right-handed subjects. This offers the opportunity to
simultaneously study two cognitive functions, language and verbal encoding, using
one task. TLE is a network disease which predisposes afflicted patients to cortical reorganization
and inserting uncertainties regarding hemisphere dominance. Atypical
language representation in connection with left-handedness should be interpreted
with caution irrespective of which paradigm is chosen.
Keywords: TLE, fMRI, handedness, lateralization index, language lateralization
language lateralization.
Purpose: To explore two conceptually different fMRI paradigms’ ability to lateralize
language.
Methods: A verbal encoding paradigm and a word generation task were performed by
six patients (four right-handed) with therapy-resistant temporal lobe epilepsy (TLE),
and by ten healthy individuals (five right-handed). FMRI laterality indices (LI) and
laterality curves for the anterior cerebral language regions were calculated. Typical
lateralization was defined as left-hemisphere dominance, and a typical as bilateral or
right-hemisphere dominance.
Results: Both paradigms showed predominantly left-sided activation in the anterior
language regions, with typical contralateral cerebellar activity. Thirteen out of sixteen
subjects showed concordant language lateralization results for both paradigms.
Two subjects, both left-handed, showed discordant language lateralization results.
Laterality curves added information for individual subjects with uncharacteristic
results. The verbal encoding task showed overall more widespread activation
compared to the word generation task.
Conclusion: Our results indicate valid language lateralization obtained by the fMRI
verbal encoding paradigm for right-handed subjects. This offers the opportunity to
simultaneously study two cognitive functions, language and verbal encoding, using
one task. TLE is a network disease which predisposes afflicted patients to cortical reorganization
and inserting uncertainties regarding hemisphere dominance. Atypical
language representation in connection with left-handedness should be interpreted
with caution irrespective of which paradigm is chosen.
Keywords: TLE, fMRI, handedness, lateralization index, language lateralization
Original language | English |
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Number of pages | 8 |
Journal | Annals of neuroscience and psychology |
Publication status | Published - 2015 Feb |
Subject classification (UKÄ)
- General Language Studies and Linguistics
- Neurology