title: Effects of low-frequency cranial electrostimulation on the rest-activity rhythm and salivary cortisol in Alzheimer's disease.
abstract: OBJECTIVE
  In previous studies, cranial electrostimulation (CES) had positive effects on sleep in depressed patients and in patients with vascular dementia. The present study examined the effects of low-frequency CES on the rest-activity rhythm and cortisol levels of patients with probable Alzheimer's disease (AD).
  
  
  METHODS
  It was hypothesised that a decreased level of cortisol would parallel a positive effect of low-frequency CES on nocturnal restlessness. Sixteen AD patients were randomly assigned to an experimental group (n = 8) or a control group (n = 8). The experimental group was treated with CES, whereas the control group received sham stimulation, for 30 minutes a day, during 6 weeks. The rest-activity rhythm was assessed by actigraphy. Cortisol was measured repeatedly in the saliva throughout the day by means of salivette tubes.
  
  
  RESULTS
  Low-frequency CES did not improve the rest-activity rhythm in AD patients. Moreover, both groups showed an increase instead of a decrease in the level of cortisol.
  
  
  CONCLUSIONS
  These preliminary results suggest that low-frequency CES has no positive effect on the rest-activity rhythm in AD patients. An alternative research design with high-frequency CES in AD is discussed.
authors.affiliation: Department of Clinical Neuropsychology, Vrije Universiteit, Van der Boechorststraat 1, 1081 BT Amsterdam, The Netherlands. EJA.Scherder@psy.vu.nl
authors.forename: Erik
authors.initials: E
authors.lastname: Scherder
authors.forename: Dirk
authors.initials: D
authors.lastname: Knol
authors.forename: Eus
authors.initials: E
authors.lastname: van Someren
authors.forename: Jan-Berend
authors.initials: JB
authors.lastname: Deijen
authors.forename: Rob
authors.initials: R
authors.lastname: Binnekade
authors.forename: Fred
authors.initials: F
authors.lastname: Tilders
authors.forename: Joseph
authors.initials: J
authors.lastname: Sergeant
mesh_terms: D000204:Activity Cycles; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism / Q000503:physiopathology* / Q000628:therapy*; D001921:Brain / Q000503:physiopathology*; D004599:Electric Stimulation Therapy; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D012463:Saliva / Q000378:metabolism*; D016896:Treatment Outcome
chemical_list: D006854:Hydrocortisone