Blepharospasm: Update on Epidemiology, Clinical Aspects, and Pathophysiology

Abstract

Blepharospasm (BSP) is a rather distressing form of focal dystonia. Although many aspects of its pathophysiological mechanisms are already known, we lack fundamental evidence on etiology, prevention, and treatment. To advance in our knowledge, we need to review what is already known in various aspects of the disorder and use these bases to find future lines of interest. Some of the signs observed in BSP are cause, while others are consequence of the disorder. Non-motor symptoms and signs may be a cue for understanding better the disease. Various cerebral sites have been shown to be functionally abnormal in BSP, including the basal ganglia, the cortex, and the cerebellum. However, we still do not know if the dysfunction or structural change affecting these brain regions is cause or consequence of BSP. Further advances in neurophysiology and neuroimaging may eventually clarify the pathophysiological mechanisms implicated. In this manuscript, we aim to update what is known regarding epidemiology, clinical aspects, and pathophysiology of the disorder and speculate on the directions of research worth pursuing in the near future.

Dextromethorphan is Effective for Essential Blepharospasm

“…Different brain regions have been shown to function abnormally in the blepharospasm, including the basal ganglia, the cortex, and the cerebellum. However, it is unclear whether the functional changes in these sites are the cause or outcome of the disease [2]. The precise neural circuitry involved in the pathogenesis of essential blepharospasm is not clear either.…”

“…Severe blepharospasm may cause traffic accidents [1]. Since the etiology and mechanism of essential blepharospasm is unknown, current treatment is mostly directed to relief the symptoms [2]. Many therapies such as biofeedback, hypnosis, acupuncture, psychotherapy have been tried but with little success.…”

Voxel-Mirrored Homotopic Connectivity of Resting-State Functional Magnetic Resonance Imaging in Blepharospasm

“…This disease occurs mostly in adults and manifested with an increased frequency of blinking in the early stage and consistent closed-eyes or even functional blindness in the late stages. Furthermore, BSP will lead to poor quality of life, decline in employment, anxiety, and depression ( Muller et al, 2002 ; Biuk et al, 2013 ; Valls-Sole and Defazio, 2016 ; Bedarf et al, 2017 ). However, the pathophysiology of BSP remains unclear.…”

Spinocerebellar Ataxia Type 31 with Blepharospasm

“…Blepharospasm is a form of focal dystonia characterized by involuntary orbicularis oculi muscle spasms ( 4 , 5 ). Studies of patients with blepharospasm have demonstrated hyperactivity of various brain regions, including the lenticular nucleus and thalamus ( 4 ). Recent studies also demonstrated cerebellar involvement in blepharospasm patients ( 4 , 6 ).…”