Auditory cortical activation in severe-to-profound hearing-impaired patients monitored by SPET.
Single photon emission tomography was used to map blood flow increase in temporal and parietal cortex after auditory stimulation in 25 subjects: 10 normal-hearing, 10 severe-profound hearing-impaired and 5 totally deaf. After a 500 Hz pure tone stimulation, a marked perfusion increase was observed, particularly at the level of the contralateral auditory temporal cortex. Blood flow increase in temporal and parietal cortical areas of normal subjects was significantly higher than that observed in severe-to-profound hearing-impaired patients. In all cases, following 500 Hz pure tone acoustic stimulation, the most lateral sagittal slice tomograms (48.75 and 56.25 mm) showed the highest blood flow increase. Statistically significant differences were also observed between normal subjects and hearing-impaired patients in the 48.75 mm sagittal tomogram. In 2 hearing-impaired patients, the single photon emission tomography pattern showed activation of the intermediate sagittal tomogram, suggesting a possible new tonotopic cortical arrangement. No significant activation was present in totally deaf patients. In conclusion, Single Photon Emission Tomography appears to be a useful tool in the evaluation of auditory cortical activation and cortical plasticity, in severe-to-profound hearing-impaired patients. Moreover, it could be a useful test for the study of auditory central pathways.
Di Nardo
W
W
Institute of Otorhinolaryngology, Catholic University of Rome, Rome, Italy.
Di Giuda
D
D
Scarano
E
E
Picciotti
P M
PM
Galla
S
S
De Rossi
G
G
D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D001301:Audiometry, Pure-Tone; D001306:Auditory Pathways / Q000000981:diagnostic imaging; D001309:Auditory Threshold; D003638:Deafness / Q000000981:diagnostic imaging*; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000098:blood supply* / Q000000981:diagnostic imaging*; D012720:Severity of Illness Index; D013702:Temporal Lobe / Q000098:blood supply* / Q000000981:diagnostic imaging*; D015899:Tomography, Emission-Computed, Single-Photon