Respiratory tracking of dichotically presented tonal amplitudes

This study investigated the possible existence of a lateralized auditory sensorimotor integration system between amplitude modulations of a tone and respiratory movements controlling them. A dichotic pursuit auditory tracking paradigm was utilized that has previously implicated a lateralized sensorimotor system for lingual and mandibular control of frequency modulated acoustic stimuli. Thirty-two normal right-handed subjects tracked a continuously varying pure tone, the target, randomly fluctuating from 65 to 95 dB SPL, and presented to one ear, with another tone, the cursor, controlled by inhalation/exhalation movements (lung volume changes) and presented to the other ear. Target and cursor tones were counterbalanced for right and left ear presentation across 40 one-minute trials. Results failed to show a statistically significant laterality effect. Significant interactions revealed an advantage for cursor/RE, target/LE laterality presentation during the second half of each 20-trial block, and a predominant within trial REA. Tracking efficiency was far below that observed for upper articulator control of the cursor. A tentative conclusion is that the particular subpart of the speech musculature used in the tracking paradigm is more relevant to a lateralized sensorimotor integration system than the compliance between the sensory result of the movement, re: speech production and the movement pattern itself.