Phrase Recognition

Lubdha M. Shah, MD

Key Facts

Anatomy-based Imaging Issues

Syntactic processing predominantly shows brain activity in left hemisphere
Sentence processing associated with expanded activation of frontal operculum and temporal poles

Protocol

1 mm isotropic MPRAGE acquisition for anatomic template
BOLD echoplanar images

Timing

Block design alternating 20 seconds of auditory stimuli with 20 seconds of no stimuli
4-minute duration

Instructions

Auditory stimuli were delivered to sound-blocking pneumatic headphones
Phrases describe a common word
- e.g., “Jewelry we wear around our neck,” “the funny guys at the circus,” and “water falling from the sky”
Subject instructed to think silently of a word that each phrase describes

Assessment

Expected language regions: Wernicke area, Broca area, lateral premotor cortex, supplementary motor area, left dorsolateral prefrontal cortex

Preprocessing

Distortion, motion, slice timing correction
Coregistration to MPRAGE or T2 anatomic images for overlay of BOLD signal

Statistical Analysis

General linear model
- Comparing “on” epochs with “off” epochs

(Left) Axial MPRAGE with BOLD signal overlay shows activation in bilateral superior temporal gyri in the expected region of the auditory cortex

. In the covert phrase recognition task, the patient hears descriptive phrases (e.g., “those funny guys at the circus”) and silently thinks of the word each phrase describes. During alternate periods, the patient hears scrambled speech. (Right) 3D surface rendering of the same patient shows activation in the left frontal operculum

and superior temporal gyrus

(Left) Axial MPRAGE with BOLD signal overlay reveals activation in bilateral superior temporal gyri

. An auditory responsive naming paradigm is useful for language lateralization, particularly for the localization of posterior language regions (Wernicke area). The task also localizes frontal speech areas

as it requires the patient to generate a word to a given verbal descriptor. (Right) 3D surface rendering of the same patient shows activation in the left inferior frontal