en Clinical Medicine Clinical Medicine مقاله پژوهشی Original Research Article <p dir="ltr" style="text-align: justify;"><span style="font-size:16px;"><span style="font-family:Times New Roman;"><strong><span style="background:#2D7F8F;"><span style="color:white;">&nbsp;Background & Objective:</span></span></strong> <span style="color:black;">The blink reflex recovery cycle indicates the excitability of interneurons in the brainstem. In this study, we aimed to investigate the blink reflex and R2 recovery cycle in patients with benign essential blepharospasm (BEB).</span><br> <strong><span style="letter-spacing:-.1pt;background:#2D7F8F;"><span style="color:white;">&nbsp;Materials & Methods:</span></span> </strong><span style="letter-spacing:-.1pt;"><span style="color:black;">This prospective case-control study compared the blink reflex and R2 recovery in 18 BEB patients with 18 age- and gender-matched healthy individuals. The blink reflex was measured in a stimulation duration of 0.2 ms, and R1, R2, and R2&rsquo; were recorded for all subjects. The R2 recovery cycle was measured by stimulation of the supraorbital nerve at four interstimulus intervals (ISI) of 200, 300, 500, and 1000 ms, with the same intensity as the previous test. The R2 recovery index was calculated and compared with the control group via independent sample t-test. Two-tailed P-value less than 0.05 was considered statistically significant.</span></span><br> <strong><span style="background:#2D7F8F;"><span style="color:white;">&nbsp;Results: </span></span>&nbsp;</strong><span style="letter-spacing:-.1pt;"><span style="color:black;">The blink reflex (R1, R2, and R2&rsquo; responses) distal latencies and amplitudes in the BEB group were not significantly different from the control group (<em>P</em>>0.05). The R2 recovery index in all intervals was significantly higher in the BEB group than the control group (<em>P</em>=0.00). The most significant difference between the BEB and control groups regarding the R2 recovery indices was observed at ISIs of 300 and 200 ms (80.36 vs. 16.99 and 75.70 vs. 12.57, respectively). There was a negative correlation between the patient&rsquo;s age at the onset of disease and the R2 recovery index; however, it was not statistically significant (<em>P</em>>0.05).</span></span><br> <strong><span style="background:#2D7F8F;"><span style="color:white;">&nbsp;Conclusion: </span></span></strong>&nbsp;<span style="color:black;">Our findings showed that the R2 recovery reflex was higher in BEB patients than the normal population. Therefore, it can be a helpful index for differentiating BEB cases from psychogenic or malingering ones.</span></span></span></p> Blepharospasm, Blink reflex, R2 recovery cycle 330 334 http://journal.zums.ac.ir/browse.php?a_code=A-10-5267-2&slc_lang=en&sid=1 Maryam Pouranian pouranian.maryam@yahoo.com 5200319475328460088798 5200319475328460088798 No Dept. of Neurology, Rasoul Akram Hospital, Iran University of Medical Science, Tehran, Iran Mohammad Rohani mohammadroohani@gmail.com 5200319475328460088799 5200319475328460088799 No Dept. of Neurology, Rasoul Akram Hospital, Iran University of Medical Science, Tehran, Iran Maziar Emamikhah maziar.emamikhah@yahoo.com 5200319475328460088800 5200319475328460088800 No Dept. of Neurology, Rasoul Akram Hospital, Iran University of Medical Science, Tehran, Iran Gholamali Shahidi gholamali.shahidi@gmail.com 5200319475328460088801 5200319475328460088801 No Dept. of Neurology, Rasoul Akram Hospital, Iran University of Medical Science, Tehran, Iran Mona Ramezani Ghamsari monaramezanighamsari@gmail.com 5200319475328460088802 5200319475328460088802 No Dept. of Neurology, Rasoul Akram Hospital, Iran University of Medical Science, Tehran, Iran Mahla Babaie mahla_babaie@gmail.com 5200319475328460088803 5200319475328460088803 No Student Research Committee, Iran University of Medical Science, Tehran, Iran Mansoureh Babadi babadi.mansoureh@gmail.com 5200319475328460088804 5200319475328460088804 No tudent Research Committee, Ahvaz Jundishapur University of Medical Science, Ahvaz, Iran Mahdi Safdarian Mahdi.safdarian@gmail.com 5200319475328460088805 5200319475328460088805 No Student Research Committee, Tehran University of Medical Science, Tehran, Iran Seyed Amir Hassan Habibi Habibi.sah@iums.ac.ir 5200319475328460088806 5200319475328460088806 Yes Dept. of Neurology, Rasoul Akram Hospital, Iran University of Medical Science, Tehran, Iran