Detection of Subclinical Motor Speech Deficits after Presumed Low-Grade Glioma Surgery

Motor speech performance was compared before and after surgical resection of presumed low-grade gliomas. This pre- and post-surgery study was conducted on 15 patients (mean age = 41) with low-grade glioma classified based on anatomic features. Repetitions of /pa/, /ta/, /ka/, and /pataka/ recorded before and 3 months after surgery were analyzed regarding rate and regularity. A significant reduction (6 to 5.6 syllables/s) pre- vs. post-surgery was found in the rate for /ka/, which is comparable to the approximate average decline over 10-15 years of natural aging reported previously. For all other syllable types, rates were within normal age-adjusted ranges in both preoperative and postoperative sessions. The decline in /ka/ rate might reflect a subtle reduction in motor speech production, but the effects were not severe. All but one patient continued to perform within normal ranges post-surgery; one performed two standard deviations below age-appropriate norms pre- and post-surgery in all syllable tasks. The patient experienced motor speech difficulties, which may be related to the tumor's location in an area important for speech. Low-grade glioma may reduce maximum speech-motor performance in individual patients, but larger samples are needed to elucidate how often the effect occurs.