Using neuroimaging and neuromodulation to study changes in brain functioning with therapy.

This article reviews the concepts underlying functional neuroimaging and its use to study brain function change as a result of recovery and neurorehabilitation for speech, voice, and swallowing. The role of neurovascular coupling for quantifying brain function change in response to behavioral demands is explained. The types of changes in brain function that are measured and how they should be interpreted are addressed for the study of brain function abnormalities in developmental and acquired speech, voice, and swallowing disorders. One challenge is to separate changes in brain function due to recovery from those that are secondary to the development of compensatory skills during therapy. The advantages of functional magnetic resonance imaging and functional near-infrared spectroscopy are compared. The use of transcranial magnetic stimulation for the study of brain function is reviewed. In addition, more recent methods for the modulation of brain function using transcranial magnetic and electrical stimulation over the cortex are examined. These technologies can be used by clinical investigators to gain better understanding of normal brain function and for learning how abnormalities in brain function might be addressed. Both are likely to lead to new therapeutic approaches to neurorehabilitation of speech, voice, and swallowing disorders.