Cortical Silent Period in Laryngeal Dystonia (cSPDystonia)

University of Split

Status: Enrolling

Conditions: Spasmodic Dysphonia; Laryngeal Dystonia

Treatments: Other: Transcranial Magnetic Stimulation (TMS)

Study type: Observational

Funder types: Other

Identifiers

NCT05580302

003-08/22-03/0003

Details and patient eligibility

About

The goal of this observational study is to evaluate the cortical silent period (cSP) in cricothyroid muscle (CT) in laryngeal dystonia and control healthy subjects. The study will provide norms related to latency and amplitude of motor evoked potentials (MEPs) and duration of cSP in CT muscle in laryngeal dystonia and control healthy subjects.

Findings may give a baseline in comparison to findings in laryngeal diseases and insight into maladaptive cortical control function during phonation in laryngeal diseases like laryngeal dystonia.

Full description

Transcranial magnetic stimulation (TMS)-induced cSP provide a noninvasive "in vivo" insight into how the human motor cortical inhibitory pathway function by generating electric current at a specific brain area through electromagnetic induction. The stimulator generates a changing electric current within the coil, which induces a magnetic field that then causes a second inductance of inverted electric charge within the brain itself. A single supra-threshold pulse of TMS over the human motor cortex elicits multiple descending volleys (I-waves) that generate a motor evoked potential (MEP) followed by a period of electromyographic silence in the tonically contracted target muscle (cSP). To date, methodologies for mapping the primary motor cortex (M1) with TMS and intraoperatively by electrical stimulation techniques have been previously developed to record corticobulbar motor evoked potentials (MEP) from laryngeal muscles. Except for estimating the amplitude and latency of MEPs recorded from laryngeal muscles, the cSP was investigated from thyroarytenoid muscle (TA) as a measure of M1 excitability in the TMS study. Previous work using TMS has indicated reduced inhibition to be characteristic of focal laryngeal dystonia. According to investigators' knowledge, cSP from other laryngeal muscles other than TA has not been investigated so far.

The proposed study analyses neurophysiological CNS data, including motor evaluation of corticospinal and corticobulbar pathways by recording MEPs and cSP using TMS.

Firstly, a questionnaire will be given to check for any previous neurological conditions, and subjects will provide signatures on participation in the study. The MRI of the subject's brain will be performed, and then 3D reconstructed for the use of TMS. The evaluation of the MRI will be done by radiologists at University Hospital Split. With the subject comfortably seated, the MRI is co-registered to the subject's head using the tracking system with TMS's unique forehead tracker. After TMS measurement of the MEP and cSP of CT muscle of individual subjects will be recorded. Data collected will be analyzed using MATLAB 2022a (MathWorks, USA). Measurements and data evaluation will be performed at the School of Medicine University in Split.

An otorhinolaryngology specialist will be consulted for the correct placement of the recording electrodes (Hookwire IOM electrodes, disposable subdermal needle electrode, 0.4 x 13 mm, SGM d.o.o, G. Novaka 22 a, 21000 Split, Croatia) into the CT muscle.

Enrollment: 20 estimated patients

Sex: All

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• adults (18-65 years old), no implanted metals in the body (e.g. pacemaker, metal prosthesis in the skull and oral cavity).

Exclusion criteria

• pregnancy, other neurological disorders (except laryngeal dystonia in the laryngeal dystonia group), psychiatric disorders, epilepsy or history of previous epilepsy attack, using of brain-affecting pharmaceuticals, traumatic, tumor, infectious, metabolic brain lesions, heart conditions.

The composition of the group is represented is both gender, various age gap, and different height.

Trial design

20 participants in 2 patient groups

Laryngeal Dystonia

Description:

The study will be performed on 10-15 (maximal 20) subjects with diagnosed laryngeal dystonia who meet the exclusion/ inclusion criteria. Inclusion criteria: adults (18-65 years old) who have confirmed diagnosis of laryngeal dystonia, no implanted metals in body (e.g. pacemaker, metal prosthesis in skull and oral cavity). Exclusion criteria: pregnancy, other neurological disorders, psychiatric disorders, epilepsy or history of previous epilepsy attack, using of brain affecting pharmaceuticals, traumatic, tumor, infectious, metabolic brain lesions, heart conditions (15 ). The composition of the group is represented is both gender, various age gap, and different height. Before the beginning of testing, all subjects with a confirmed diagnosis of laryngeal dystonia will be once again evaluated by a specialist otorhinolaryngologist at the University Hospital of Split. Medical documentation of the examination will be available for further analysis.

Treatment:

Other: Transcranial Magnetic Stimulation (TMS)

Healthy subjects

Description:

The study will be performed on 20 healthy volunteering subjects who meet the exclusion/ inclusion criteria. Inclusion criteria: healthy adults (18-65 years old), no implanted metals in body (e.g. pacemaker, metal prosthesis in the skull and oral cavity) Exclusion criteria: pregnancy, neurological disorders, psychiatric disorders, epilepsy or history of previous epilepsy attack, using of the brain affecting pharmaceuticals, traumatic, tumor, infectious, metabolic brain lesions, heart conditions. The composition of the group is represented is both gender, various age gap, and different height.

Treatment:

Other: Transcranial Magnetic Stimulation (TMS)