Object naming is a more sensitive measure of speech localization than number counting: Converging evidence from direct cortical stimulation and fMRI Nicole M. Petrovich Brennan, Stephen Whalen, Daniel de Morales Branco, James P. O'Shea, Isaiah H. Norton, and Alexandra J. Golby ⁎ Department of Neurological Surgery, Brigham and Women’s Hospital and Harvard Medical School, 75 Francis Street, CA 138-F, Boston, MA 02115, USA Received 2 January 2007; revised 24 March 2007; accepted 16 April 2007 Available online 13 May 2007 Using direct cortical stimulation to map language function during awake craniotomy is a well-described and useful technique. However, the optimum neuropsychological tasks to use have not been detailed. We used both functional MRI (fMRI) and direct cortical stimulation to compare the sensitivity of two behavioral paradigms, number counting and object naming, in the demonstration of eloquent cortical language areas. Fifteen patients with left hemisphere lesions and seven healthy control subjects participated. Patients had both preoperative fMRI at 3 T and direct cortical stimulation. Patients and controls performed object naming and number counting during fMRI at 3 T. Laterality indices were calculated from the fMRI maps for the Number- counting > Object-naming and Object-naming > Number-counting contrasts. The same number-counting and object-naming paradigms were tested during awake craniotomy and assessed for sensitivity to speech disruption. In all patients during intraoperative cortical stimulation, speech disruption occurred at more sites during object naming than during number counting. Subtle speech errors were only elicited with the object-naming paradigm, whereas only speech arrest and/or hypophonia were measured using the number counting paradigm. In both patients and controls, fMRI activation maps demonstrated greater left lateralization for object naming as compared to number counting in both frontal and temporal language areas. Number counting resulted in a more bihemispheric distribution of activations than object naming. Both cortical stimulation testing and fMRI suggest that automated speech tasks such as number counting may not fully engage putative language networks and therefore are not optimal for language localization for surgical planning. © 2007 Published by Elsevier Inc. Introduction Awake craniotomy for the purpose of language mapping is a well-described and useful technique (Haglund et al., 1994; Berger and Rostomily, 1997; Berger et al., 1989; Meyer et al., 2001; Ojemann et al., 1989). Typically, as the surgeon performs direct bipolar electrical cortical stimulation with simultaneous electro- corticography, a neuropsychologist monitors the patient's perfor- mance on a language task. Disruption of the task during cortical stimulation is taken to indicate that the underlying cortex is essential for the performance of that task. Surgical resection of the lesion is then performed respecting a margin, generally 1 cm, of the positive response sites. Unfortunately, even when these margins are respected, patients may exhibit postoperative language deficits including difficulty with comprehension, speech production, naming, repetition, read- ing or writing. One possible reason such deficits occur may be because a variety of language tasks are not individually tested during cortical mapping. As a result, it is possible that the testing that is performed is not sensitive enough to detect the cortical localization of all possible language function in an area. Hamberger et al. (2005), for example, demonstrated that the use of different language tasks during direct cortical stimulation can affect clinical language outcome. They found that patients who had resections that included sites at which auditory responsive naming was disrupted showed more postoperative aphasia than patients who did not have auditory responsive naming sites removed. This aphasia occurred despite the fact that those patients had their visual naming sites spared. Ideally then, patients would be mapped using several language tasks. However, intraoperative constraints of time, patient cooperation, sedation, and positioning preclude comprehensive language testing. There- fore, it is important to systematically examine the sensitivity of various language tasks so that we can maximize the efficiency of intraoperative language testing and better avoid postoperative deficits. www.elsevier.com/locate/ynimg NeuroImage 37 (2007) S100 – S108 ⁎ Corresponding author. Fax: +1 617 713 3050. E-mail address: agolby@bwh.harvard.edu (A.J. Golby). Available online on ScienceDirect (www.sciencedirect.com). 1053-8119/$ - see front matter © 2007 Published by Elsevier Inc. doi:10.1016/j.neuroimage.2007.04.052