Frances J. Freeman

Magnetic resonance imaging findings and correlations in spasmodic dysphonia patients

A sample of 19 spasmodic dysphonia (SD) patients was selected from a larger population of such patients to undergo magnetic resonance imaging (MRI), auditory brain stem response (ABR) testing, speech analysis, and extensive physical examination. Six patients had abnormal spin-echo MRI findings, ranging from infarcts within the basal ganglia to demyelinating lesions within the supralateral angles of the lateral ventricles. A weakly positive correlation was noted between the abnormal MRI findings and an abnormal ABR. The lack of a significant correlation between the MRI findings and other predictors of brain stem and midbrain disease, and the current spatial resolution limitations of MRI, suggest that we are visualizing the associated lesions rather than the actual foci of SD. The range of MRI findings is consistent with the concept that SD is a voice disorder in a heterogeneous patient population.

Phonation in stuttering: A review of current research☆

Abstract Current research including studies which implicate the phonatory mechanism in stuttering as well as physiological studies offering direct evidence of abnormal laryngeal activity in stuttering are reviewed. It is concluded that while present research does not support claims for laryngeal causation of stuttering, the evidence is strong that abnormal laryngeal behaviors are an important aspect of the disrupted peripheral speech physiology that characterizes stuttering. Since this is true, it follows that abnormal laryngeal behavior deserves consideration in the diagnosis and management of stuttering.

Systems Architecture for Quantification of Dynamic Myoelectric and Kinematic Activity of the Human Vocal Tract

This paper describes a systems architecture useful for scientific investigations that require the acquisition and analysis of multiple, time-synchronous signals in large volume. The architecture has recently been developed by this group to enhance our capability to research and quantify central nervous system function in the production of normal and pathologic speech. The architecture utilizes modern advances in desktop microcomputers and has been designed so that vocal motor control laboratories (or similar settings) with modest funding can more fully participate in comprehensive investigations of speech production. Research experiments organized with this architecture may involve many more subjects and measures than previously possible without significant increases in time and personnel resources. This paper will demonstrate the technique and practicality of this architecture as it is being used to successfully guide research to map hierarchic central nervous system regions of involvement in two speech disorders: Spasmodic dysphonia and stuttering. The architecture has broad usefulness to many areas of otolaryngology and health science.

Brain Electrical Activity Mapping: Applications to Vocal Motor Control Disorders

Brain Electrical Activity Mapping (BEAM) is a recently developed analytic tool for examining both electroencephalographic (EEG) and evoked potential (EP) data. Specifically BEAM overcomes several of the limitations which have hampered full use of these approaches, especially as applied to disorders of speech motor control. This chapter discusses rationale for development of BEAM, briefly describes the technology, and presents findings from initial studies of patients with two vocal motor control disorders — spasmodic dysphonia (SD) and stuttering (ST).

Brain electrical activity mapping in adductor spasmodic dysphonia

Brain electrical activity mapping (BEAM) was employed to study ten patients exhibiting adductor spasmodic dysphonia. BEAM is a recent neural imaging technique which utilizes digital signal processing and color graphics capabilities to generate mappings of the scalp distribution of ongoing cortical EEG activity, as well as cortical evoked response amplitudes to sensory stimulation. The technique provides data for EEG eyes open, EEG eyes closed, and auditory, visual and somatosensory evoked potentials. Patient responses were compared with normative data previously established for the BEAM technique, and significance probability mappings of patient‐to‐normal deviations generated. Results suggest diverse neurophysiologic abnormalities among the spasmodic dysphonic patients. Specific findings varied from patient to patient but included abnormal EEG activity and abnormal evoked responses in a significant proportion of patients tested. Regions of frequent “lesion” overlap were also present. Relationships of BEAM...

Studies of apraxic speech production

A series of five studies of apraxic speakers generated the following conclusions: (1) The major residual errors for an apraxic with ten years of therapy appeared to result from poor temporal coordination of expiration, vocal fold adduction, and articulatory gesture. (2) VOTs for this patient differed markedly from those of normals, and related to perceived voicing errors for stops. (3) VOTs for four other apraxic speakers were also abnormal. (4) Therapy directed toward teaching the first patient to produce more appropriate voice onset times succeeded in establishing two discreet categories of stops, but VOTs still differed from those of normals and lacked “natural quality.” (5) Lack of success in teaching the patient to produce normal stops may result from the categorical perception of clinicians providing feedback for modification. Results of these studies have implications relating to (1) the nature of the apraxic disorder, (2) use of acoustic analysis procedures for diagnosis and management of speech production disorders, (3) limitations of clinician perception in providing feedback for modification of in‐category (distorted) phoneme production errors. [This work was supported in part by NIDR Grant DE‐01774.]