TY - JOUR
T1 - Restored speech comprehension linked to activity in left inferior prefrontal and right temporal cortices in postlingual deafness
AU - Mortensen, Malene Vejby
AU - Mirz, Frank
AU - Gjedde, Albert
N1 - Funding Information:
This research was supported by The National Association of Hearing Impaired in Denmark, Desirée and Niels Ydes Foundation and the Danish National Research Foundation's Center of Functionally Integrative Neuroscience. We appreciate the help of Anders B. Rodell, PhD, with average MRI images and Stig Madsen with sound stimuli.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2006/6
Y1 - 2006/6
N2 - The left inferior prefrontal cortex (LIPC) is involved in speech comprehension by people who hear normally. In contrast, functional brain mapping has not revealed incremental activity in this region when users of cochlear implants comprehend speech without silent repetition. Functional brain maps identify significant changes of activity by comparing an active brain state with a presumed baseline condition. It is possible that cochlear implant users recruited alternative neuronal resources to the task in previous studies, but, in principle, it is also possible that an aberrant baseline condition masked the functional increase. To distinguish between the two possibilities, we tested the hypothesis that activity in the LIPC characterizes high speech comprehension in postlingually deaf CI users. We measured cerebral blood flow changes with positron emission tomography (PET) in CI users who listened passively to a range of speech and non-speech stimuli. The pattern of activation varied with the stimulus in users with high speech comprehension, unlike users with low speech comprehension. The high-comprehension group increased the activity in prefrontal and temporal regions of the cerebral cortex and in the right cerebellum. In these subjects, single words and speech raised activity in the LIPC, as well as in left and right temporal regions, both anterior and posterior, known to be activated in speech recognition and complex phoneme analysis in normal hearing. In subjects with low speech comprehension, sites of increased activity were observed only in the temporal lobes. We conclude that increased activity in areas of the LIPC and right temporal lobe is involved in speech comprehension after cochlear implantation.
AB - The left inferior prefrontal cortex (LIPC) is involved in speech comprehension by people who hear normally. In contrast, functional brain mapping has not revealed incremental activity in this region when users of cochlear implants comprehend speech without silent repetition. Functional brain maps identify significant changes of activity by comparing an active brain state with a presumed baseline condition. It is possible that cochlear implant users recruited alternative neuronal resources to the task in previous studies, but, in principle, it is also possible that an aberrant baseline condition masked the functional increase. To distinguish between the two possibilities, we tested the hypothesis that activity in the LIPC characterizes high speech comprehension in postlingually deaf CI users. We measured cerebral blood flow changes with positron emission tomography (PET) in CI users who listened passively to a range of speech and non-speech stimuli. The pattern of activation varied with the stimulus in users with high speech comprehension, unlike users with low speech comprehension. The high-comprehension group increased the activity in prefrontal and temporal regions of the cerebral cortex and in the right cerebellum. In these subjects, single words and speech raised activity in the LIPC, as well as in left and right temporal regions, both anterior and posterior, known to be activated in speech recognition and complex phoneme analysis in normal hearing. In subjects with low speech comprehension, sites of increased activity were observed only in the temporal lobes. We conclude that increased activity in areas of the LIPC and right temporal lobe is involved in speech comprehension after cochlear implantation.
KW - Cochlear implants
KW - Hearing
KW - Left inferior prefrontal cortex
KW - PET
KW - Speech comprehension
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U2 - 10.1016/j.neuroimage.2005.12.020
DO - 10.1016/j.neuroimage.2005.12.020
M3 - Article
C2 - 16459106
AN - SCOPUS:33646831504
SN - 1053-8119
VL - 31
SP - 842
EP - 852
JO - NeuroImage
JF - NeuroImage
IS - 2
ER -