title: Lower limb flexor reflex: Comparisons between drug-induced akathisia and restless legs syndrome.
abstract: Akathisia is characterized by restlessness and crawling sensations similar to restless legs syndrome (RLS). Long latency flexor reflex (LLFR) which has helped to advance RLS pathophysiology has never been investigated in akathisia. Due to the clinical commonalities of akathisia and RLS, we investigated the behavior of LLFR in patients with akathisia aiming to understand pathophysiology of akathisia.
  
  
  
  Seven patients with neuroleptic-induced akathisia, 12 drug-naïve patients with primary RLS and 17 healthy subjects were prospectively enrolled in the study. LLFR was recorded from unilateral tibialis anterior (TA) and long head of biceps femoris (BF) muscles after stimulating the sole by trains of electrical stimuli. We measured amplitude, latency, duration, presence of response and compared between three groups.
  
  
  
  One-way ANOVA showed mean durations of early and late responses recorded over TA were the longest in akathisia group compared to both RLS group and healthy subjects (p=0.012). The spatial spread of LLFR in akathisia patients was comparable to those of healthy subjects whereas presence of response on BF was significantly less in akathisia than RLS group.
  
  
  
  Our findings indicate increased excitability of LLFR pathway in akathisia group. These findings are probably due to lack of inhibition originated in regions other than those known to downregulate in RLS.
authors.affiliation: Department of Neurology, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey. Electronic address: draysegulgunduz@yahoo.com.
authors.forename: Aysegul
authors.initials: A
authors.lastname: Gunduz
authors.affiliation: Department of Neurology, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey; Department of Psychology, Uskudar University, Istanbul, Turkey.
authors.forename: Baris
authors.initials: B
authors.lastname: Metin
authors.affiliation: Department of Psychiatry, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey; Department of Psychology, Uskudar University, Istanbul, Turkey.
authors.forename: Sinem Zeynep
authors.initials: SZ
authors.lastname: Metin
authors.affiliation: Department of Psychiatry, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey.
authors.forename: Burc Cagri
authors.initials: BC
authors.lastname: Poyraz
authors.affiliation: Department of Neurology, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey.
authors.forename: Derya
authors.initials: D
authors.lastname: Karadeniz
authors.affiliation: Department of Neurology, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey.
authors.forename: Gunes
authors.initials: G
authors.lastname: Kiziltan
authors.affiliation: Department of Neurology, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey.
authors.forename: Meral E
authors.initials: ME
authors.lastname: Kiziltan
mesh_terms: D000328:Adult; D017109:Akathisia, Drug-Induced / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000294:innervation / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D012018:Reflex; D012148:Restless Legs Syndrome / Q000503:physiopathology*
keywords: Akathisia; Lower limb flexor reflex; Restless legs syndrome