title: Short latency afferent inhibition in Parkinson's disease patients with dementia.
abstract: BACKGROUND
  Cortical cholinergic deficiency occurs in Parkinson's disease (PD) and is more severe in PD dementia (PDD). Short-latency afferent inhibition (SAI) can be used as an in vivo test for the evaluation of the cholinergic circuit in the cerebral motor cortex.
  
  
  METHODS
  SAI and neuropsychological profile were studied in nondemented PD, PDD, Alzheimer's disease (AD) patients, and age-matched controls.
  
  
  RESULTS
  SAI was significantly impaired in AD cases (94.7 ± 6.2 versus 55.5 ± 4.0; P < 0.0001). In PD patients, it was not different from controls (61.4 ± 5.8 versus 55.5 ± 4.0; P = 0.412). PDD cases demonstrated a significant impairment in SAI (91.4 ± 5.2 versus 55.5 ± 4.0; P < 0.0001). A high correlation was found between SAI and Mini-Mental State Examination (r = -0.68; P < 0.0001).
  
  
  CONCLUSIONS
  These findings add further evidence that differential cholinergic deficiency occurs in PD and PDD. SAI can be a neurophysiological correlate of PDD.
authors.affiliation: Department of Neurology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Ozlem
authors.initials: O
authors.lastname: Celebi
authors.forename: Cağrı Mesut
authors.initials: CM
authors.lastname: Temuçin
authors.forename: Bulent
authors.initials: B
authors.lastname: Elibol
authors.forename: Esen
authors.initials: E
authors.lastname: Saka
mesh_terms: D000344:Afferent Pathways / Q000503:physiopathology*; D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology; D000704:Analysis of Variance; D003704:Dementia / Q000150:complications / Q000503:physiopathology*; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000503:physiopathology; D009483:Neuropsychological Tests; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation