Scherder 1999.

Methods	Randomised, double‐blind, placebo‐controlled, 6 weeks
Participants	Holland Single center 18 subjects, 9 expt, 9 control Lived in a residential home for elderly people. Age: 70 ‐ 91yrs, mean 81.7 Shortened MMSE mean 4.4/12. 7 or less/12 on this scale, (equivalent to 17 or less/20 on regular MMSE) classifies patients as having serious cognitive disturbances. Met NINCDS‐ADRDA criteria for clinical diagnosis of demetia of Alzheimers type, GDS stage 6 (midstage) with symptoms present at least 6 months, all scored 17 or less on Hamilton Rating Scale for Depression. Exclusion: history of psychiatric disorder, alcoholism, cerebral trauma, cerebrovascular disease, hydrocephalus, neoplasm, infection, epilepsy, disturbances of consciousness, focal brain abnormalities, pacemaker.
Interventions	Stimulator type: Premier 10s Waveform: asymmetric biphasic square wave, Burst mode Frequency: Bursts of trains, 9 pulses/burst, pulse freq 160Hz, burst freq 2 Hz Pulse duration: 100 microsec. Amplitude: Visible muscle twitches Electrode location: Two 2 x 3 cm electrodes between T1 and T5 on 2cm from the spine. Treatment duration: 30 min/day, 5 days/week, 6 weeks Placebo intervention: Same as experimental except no current delivered.
Outcomes	ANCOVA Neuropsycological tests: Digit span: ns Visual memory span: p < 0.004 post, ns 6 wks delayed 8 words test Immed. recall: ns Delayed recall: ns Recognition: ns Face recognition: ns Picture recognition: ns Word fluency: ns Behavioural observational scales: Beoordelingsschaal vor Oudere Patienten (BOP) Subscales Need of help: ns Other scales, i.e. aggressiveness, physical invalidity, depressed behaviour, mental invalidity, inactivity, are not presented although it is implied that these were evaluated. Behaviour Inventory: ns
Notes	Authors consider this a study evaluating the effects of TENS on midstage AD in contrast with their other studies looking at early stage AD. They conclude that this study demonstrates "that TENS has a very positive effect on the performance of midstage AD patients on Visual Memory Span.... not maintained during a period of 6 weeks without treatment."
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear