Orbicularis Oculi Morphological Alterations in Affected and Nonaffected Sides in Hemifacial Spasm

Objective demonstration of eyelid spasm relief with smartphone and custom software in hemifacial spasm patients

PURPOSE

To objectively demonstrate eyelid spasms relief in hemifacial spasm (HFS) patients using a smartphone and a custom-made software.

METHODS

Nineteen patients with HFS had standardized videos recorded with a smartphone (iPhone 6S, Apple) camera before and 15 days after receiving onabotulinumtoxinA injections. Nineteen age-matched control subjects were also assessed. The Eye Aspect Ratio (EAR) is an algorithm previously described to determine whether the eye is opened or closed. When the eye is closed, EAR tends to be closer to zero. Analogously, if the eye is wide open, values are greater. A custom-made software using the EAR concept was developed and pre- and post-treatment EARs were analyzed to assess HFS patients.

RESULTS

Botulinum toxin (BoNT) injections led to a significant increase in the average EAR of the affected side: + 10.4% (p = 0.0175) of HFS patients, compared to baseline. Mean EAR before BoNT applications were significantly lower (16.2%) on the affected side (0.25 ± 0.05) of HFS patients when compared to controls (0.30 ± 0.05, p = 0.004). After BoNT injections, no statistically significant difference was observed for the average EAR between the affected side of HFS patients (0.27 ± 0.04) and controls (p = 0.20).

CONCLUSIONS

Use of a smartphone and custom-made software objectively demonstrated eyelid spasm relief in patients with HFS. Additional refinement of this system could permit more accurate assessments of treatment response rates for each patient, making it possible to be used in clinical practice.

Orbicularis Oculi Muscle Immunohistochemical, Metabolic, and Morphometric Differences in Affected and Nonaffected Sides in Hemifacial Spasm vs Healthy Subjects

BACKGROUND

Subtle morphological alterations have been reported even in the nonaffected side of the orbicularis oculi muscle in patients with hemifacial spasm. However, no previous study assessed immunohistochemical, metabolic, and morphometric alterations in orbicularis oculi muscle fibers in affected and nonaffected sides in patients with this condition, compared with samples obtained from healthy subjects. The purpose of this study is to objectively assess and compare orbicularis oculi muscle (OOM) samples of hemifacial spasm affected and nonaffected sides and healthy subjects.

METHODS

Orbicularis oculi samples from 8 patients with hemifacial spasm who had not been previously treated and 6 healthy subjects were prepared using hematoxylin and eosin, nicotinamide adenine dinucleotide tetrazolium reductase, cytochrome oxidase, succinate dehydrogenase, Gomori staining, and monoclonal antibodies against myosin slow and myosin fast. A digital image analysis software was used for objective analysis.

RESULTS

OOM fiber area was significantly greater in both affected ( P = 0.0379) and nonaffected sides ( P = 0.0012) of HFS samples when compared with control subjects' fibers. A significantly greater number of oxidative fibers were observed in both affected and nonaffected sides of patients with HFS when compared with control subjects ( P < 0.001 for both). A significantly greater percentage of slow fibers was observed in the affected side of HFS patients ( P = 0.0012) compared with control subjects.

CONCLUSIONS

This study's findings suggest that repeated contractions might lead to OOM fiber hypertrophy, increased mitochondrial metabolism, and possible conversion of fast-twitch orbicularis oculi muscle fibers into slow-twitch fibers in patients with HFS. Alterations were observed in affected and nonaffected sides, confirming initial findings that the nonaffected side is not normal in this unique condition.