Effect of reading on surface electromyogram recordings in patients with blepharospasm. 2009

Michael J Richard, and Donald J Woodward, and Alli N McCoy, and Julie A Woodward
Division of Oculoplastic and Reconstructive Surgery, Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710, USA.

OBJECTIVE To compare the surface electromyogram recordings between patients with benign essential blepharospasm and controls while maintaining primary gaze and reading in downgaze. METHODS A university-based, prospective case series of 7 benign essential blepharospasm patients and 7 normal patients. Bilateral lower eyelid preseptal orbicularis oculi muscle potentials were recorded via surface electromyogram and video while performing a standardized 60-second task that was divided in 3 equal 20-second subtasks. Specifically, patients were asked to maintain primary gaze for the first 20-second interval, to read quietly for the second interval, and again maintain primary gaze for the third 20-second interval. Fourteen trials capturing bilateral recordings were performed in each group; qualitative and quantitative analysis of the surface electromyogram recordings was performed and compared both between patient groups and between subtasks. Blepharospasm patients were also asked to describe the effect of reading on their spasms. Specifically, they were asked before the study if reading lessened or worsened their spasms and then were asked poststudy if their symptoms lessened or worsened during the reading task. RESULTS The mean surface electromyogram potential of the orbicularis muscle was significantly less in normal eyes when compared with blepharospasm eyes for each task. Furthermore, the mean surface electromyogram potential during the reading task was significantly reduced when compared with the primary gaze task in all eyes. Only blepharospasm patients noticed this reduction subjectively. CONCLUSIONS Although conventional wisdom regarding blepharospasm suggests that reading is an exacerbating factor, short durations of reading seem to relieve spasms. This may be due to the effect of downgaze on the blink reflex and may offer possible areas of investigation for novel blepharospasm treatments.

UI MeSH Term Description Entries
D009801 Oculomotor Muscles The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris. Extraocular Muscles,Extraocular Rectus Muscles,Inferior Oblique Extraocular Muscle,Inferior Oblique Muscles,Levator Palpebrae Superioris,Musculus Orbitalis,Oblique Extraocular Muscles,Oblique Muscle, Inferior,Oblique Muscle, Superior,Oblique Muscles, Extraocular,Rectus Muscles, Extraocular,Superior Oblique Extraocular Muscle,Superior Oblique Muscle,Extraocular Muscle,Extraocular Muscle, Oblique,Extraocular Muscles, Oblique,Extraocular Oblique Muscle,Extraocular Oblique Muscles,Extraocular Rectus Muscle,Inferior Oblique Muscle,Muscle, Oculomotor,Muscles, Oculomotor,Oblique Extraocular Muscle,Oblique Muscle, Extraocular,Oblique Muscles, Inferior,Oblique Muscles, Superior,Oculomotor Muscle,Rectus Muscle, Extraocular,Superior Oblique Muscles
D011446 Prospective Studies Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group. Prospective Study,Studies, Prospective,Study, Prospective
D011932 Reading Acquiring information from text.
D001764 Blepharospasm Excessive winking; tonic or clonic spasm of the orbicularis oculi muscle. Blepharospasms
D001767 Blinking Brief closing of the eyelids by involuntary normal periodic closing, as a protective measure, or by voluntary action. Orbicularis Oculi Reflex,Reflex, Blink,Reflex, Corneal,Reflex, Orbicularis Oculi,Winking,Blink Reflexes,Corneal Reflexes,Orbicularis Oculi Reflexes,Blink Reflex,Reflexes, Blink,Reflexes, Orbicularis Oculi
D004576 Electromyography Recording of the changes in electric potential of muscle by means of surface or needle electrodes. Electromyogram,Surface Electromyography,Electromyograms,Electromyographies,Electromyographies, Surface,Electromyography, Surface,Surface Electromyographies
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man

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