Stuttering: in need of a unifying conceptual framework.

Perceptually fluent and disfluent speech reflect a continuum of coordination and can be best understood in terms of similar motor control processes. Speech movements may be considered to result from the interaction of inputs to motoneuron pools which alter the tuning of sensory-motor pathways and triggering inputs to specific muscles and muscle groups. A disorder incoordination may occur when any of these inputs is aberrantly affected by psychological, psychosocial or physiological variables. Specific phenomena associated with stuttering--adaptation, masking, whispering and voicing deviations--are interpreted in terms of these neuromotor processes. Therapeutic considerations are discussed.