Abstracts

Rationale: fMRI is used to identify language networks in increasingly younger normal and epilepsy populations. We aimed to determine success rates in fMRI language paradigm image completion in children and adolescents evaluated for epilepsy.Methods: We reviewed records of our consecutive series of children and adolescents undergoing fMRI language mapping for evaluation of epilepsy. Patients underwent fMRI at 1.5T or 3T EPI BOLD with a panel of language paradigms including verbal fluency/semantic decision, auditory comprehension, and reading comprehension. Data were processed using an IDL or SPM 2 program. Individual run images were visually read and rated as showing activation or being not interpretable (no activation or movement artifact). Results: Two children would not enter scanner due to anxiety and claustrophobia, both had significant cognitive impairments and are not further considered. 124 children entered the scanner and had images obtained. There were 11 patients between 4-7 years; 28 between 8-10; 35 between 11-13; 27 between 14-16; and 19 between 17-18. There were 471 paradigm runs or 3.8 paradigms per patient; There were 16 additional sessions in 13 patients yielding 3.4 paradigms per session. Runs per session were: 1 (n=10), 2 (n=25), 3 (n=22), 4 (n=54), 5 (n=24), 6 (n=2). 11.7% of individual runs were failures (55 of 471). 29.0% (36/124) had at least one failed run. Five had studies in English and a native language; one child had two sessions to obtain data with different paradigms (to minimize time in scanner); eight had repeat sessions due to reconsideration for (further) surgery. 10 children (7%) had failed first studies: All five patients who had repeat studies due to initial failure met with eventual success (3 had 2 attempts; 2 had three attempts); five had a failed session and were not repeated. All failed sessions occurred in patients with cognitive impairment or ADHD. Of the failed sessions, which were evenly distributed by age, 6/28 were 10 years old and younger; 4/51 were between 11-18 (χ2=63; p<0.001). Conclusions: fMRI language studies can be obtained in 95% of children studied. Repeat studies may be required in 5% to obtain usable data. Children 4 and 5 years old can be studied successfully. There is a 2% failure rate due to claustrophobia. 10% of individual runs will not obtain data emphasizing the utility of a panel of tasks. There is a higher risk for failed studies when patients are young, exhibit ADHD or cognitive impairment. Older impaired children can be successfully scanned.