Faculty

Geralyn Schulz, Ph.D, CCC-SLP, Associate Dean for Research, Columbian College of Arts and Sciences, Professor
2115 G St NW, Monroe Hall of Government, Room 207, Washington, DC 20052
Phone: 202-994-2052
e-mail: schulz@gwu.edu

Area of expertise

Motor Speech Disorders, Parkinson's Disease, Neural Bases of Speech and Language

Courses Teaching

SPHR 106: Anatomy and Physiology for Speech and Hearing

Research

Dr. Schulz's research centers on the motor control for speech and currently she is investigating the efficacy of deep brain stimulation on speech, language and limb motor systems in Parkinson's disease (PD), the effects of therapy on lingual movements in PD, the efficacy of speech treatment and various principles of motor learning for patients with traumatic brain injury, and developing a system for biofeedback of lingual movement to be used in speech therapy for persons with impaired speech production.

Recent Publications

Henriquez, V.M., Schulz, G.M., Bielamowicz, S., Ludlow, C.L. (in press) Laryngeal reflex responses are not modulated during voice and respiration tasks. J Neurophys

• While sensory input is suppressed during voluntary limb movement, trigeminal pain reduces motor activity in the jaw musculature suggesting different interactions between sensory and motor activity in different systems. The laryngeal adductor response (LAR), a protective reflex to prevent aspiration, is elicited by stimulation of afferents in the superior laryngeal nerve (SLN). Because this reflex is life-sustaining, we hypothesized that laryngeal muscle responses to sensory stimuli would not be suppressed during volitional laryngeal tasks when compared to quiet respiration. Unilateral electrical SLN stimulation elicited early R1 and late R2 responses in the thyroarytenoid muscles in ten healthy subjects. Baseline levels of muscle activity before stimulation and R1 and R2 response occurrence and amplitudes were measured during each task: quiet inspiration, prolonged vowels, humming, forced inhalation and effort closure. R1 response occurrence was not altered by task from rest while fewer R2 responses occurred only during effort closure and humming compared to rest. We tested whether R1 amplitudes during tasks were equal to either: 1) baseline muscle activity during the task plus response amplitude at rest; 2) the response amplitude at rest minus the baseline muscle activity during the task; or, 3) the response amplitude at rest. Because the R1 and R2 response amplitudes did not change from rest, task increases in motor neuron firing did not alter the LAR. These findings emonstrate that laryngeal motor neuron responses to sensory inputs are not gated during volitional tasks demonstrating the life-sustaining protective mechanisms provided by this airway reflex.

Ali, S.O., Thomasen, J.M., Schulz, G.M., Guillemin, A., Hosey, L., Varga, M., Ludlow, C.L., Braun, A.R. (2006) Alterations in CNS Activity Induced by Botulinum Toxin Treatment in Spasmodic Dysphonia: An H215O-PET Study, Journal of Speech, Language and Hearing Research, 49(5), 1127-1146.

• Speech-related changes in regional cerebral blood flow (rCBF) were measured using H2 15O positron-emission tomography in 9 adults with adductor spasmodic dysphonia (ADSD) before and after botulinum toxin (BTX) injection and 10 age and gender-matched volunteers without neurological disorders. Scans were acquired at rest and during production of continuous narrative speech and whispered speech. Speech was recorded during scan acquisition for offline quantification of voice breaks, pitch breaks, and percentage aperiodicity to assess correlations between treatment-related changes in rCBF and clinical improvement. Results demonstrated that speech-related responses in heteromodal sensory areas were significantly reduced in persons with ADSD, compared with volunteers, before the administration of BTX. Three to 4 weeks after BTX injection, speech-related responses were significantly augmented in these regions and in left hemisphere motor areas commonly associated with oral-laryngeal motor control. This pattern of responses was most strongly correlated with the objective measures of clinical improvement (decreases in the frequency of voice breaks, pitch breaks, and percentage aperiodicity). These data suggest a patho-hysiological model for ADSD in which BTX treatment results in more efficient cortical processing of sensory information, making this information available to motor areas that use it to more effectively regulate laryngeal movements.

Schulz, G.M., Varga, Jeffires, K., Ludlow, C.L., & Braun, A. (2005) Functional neuroanatomy of human vocalization studied with H2150 PET. Cerebral Cortex, 15(12), 1835-1847.

• Vocalization in lower animals is associated with a well-described visceromotor call system centered on the mesencephalic periacqueductal grey matter (PAG), which is itself regulated by paramedian cortical structures. To determine the role this phylogenetically older system plays in human phonation, we contrasted voiced and unvoiced speech using positron emission tomography and then evaluated functional connectivity of regions that significantly differentiated these conditions. Vocalization was associated with increased and highly correlated activity within the midline structures — PAG and paramedian cortices — described in lower mammalian species. Concurrent activation and connectivity of neocortical and subcortical motor regions— medial and lateral premotor structures and elements of basal ganglia thalamocortical circuitry — suggest a mechanism by which this system may have come under an increasing degree of voluntary control in humans. Additionally, areas in the temporal lobe and cerebellum were selectively activated during voiced but not unvoiced speech. These regions are functionally coupled to both visceromotor and neocortical motor areas during production of voiced speech, suggesting they may play a central role in self-monitoring and feedback regulation of human phonation.

Grants

2006 US Fulbright Senior Scholar Award; Awarded by the Australian-American Fulbright Commission; research project title: "Visual (Bio)Feedback Of Lingual Movement In Relearning Speech Following Neurologic Damage" A collaborative project between Geralyn Schulz, Ph.D., CCC-SLP, George Washington University, Washington, DC and the Motor Speech Research Center, University of Queensland, Brisbane, Australia

Professional Activities (includes gwu-related; local, regional, national associations)

• Keynote Speaker, 5th Asia Pacific Conference on Speech, Language and Hearing, Brisbane, 9-13 July, 2007
• Editorial Review Group Chair for Speech-Language-Hearing, Doody's Health Sciences Book Review Journal, Doody Publishing, Oak Park, IL.
• EDITORIAL CONSULTANT
  • Journal of Speech, Language and Hearing Research
  • Journal of Communication Disorders
  • Journal of Fluency Disorders
  • American Journal of Speech Language Pathology
  • Brain
  • Folia Phoniatrica et Logopaedia
• INTERNATIONAL EDITORIAL REVIEW BOARD MEMBER
  • Pró-Fono Revista de Atualização Científica (years 2005 – 2008) Premier Speech Language Pathology Journal of Brazil
  • Rev CEFAC, Speech Language Pathology and Audiology Journal, Brazil
• ADVISORY BOARDS
  • Communication Sciences Advisory Board, Thompson Delmar Learning, Invited and appointed November, 2003
  • Stroke Comeback Center, Board of Directors, Invited, approved and appointed March 10, 2004