Scherder 1999b.

Methods	Randomised, double‐blind, placebo‐controlled, 6 weeks
Participants	Holland Single center Study 1: 8 subjects, 4 expt, 4 control Study 2: 16 subjects, 8 expt, 8 control Study 3: 18 subjects, 9 expt, 9 control Lived in a residential home for elderly people. Meeting NINCDS‐ADRDA criteria for clinical diagnosis of probable demetia of Alzheimers type. Studies 1‐3: early stage of AD (stage 5 of GDS) Study 4: midstage of AD (stage 6 of GDS) Exclusion: history of psychiatric disorder, alcoholism, cerebral trauma, cerebrovascular disease, hydrocephalus, neoplasm, infection, epilepsy, disturbances of consciousness or focal brain abnormalities.
Interventions	Stimulation not described except that Premier 10s stimulator used. Study 1: TENS for 6 hours/day, therapist present throughout Study 2: TENS for 30 min/day, therapist present throughout Study 3: TENS without therapist present (called "isolated TENS" in the report), duration of treatment not indicated. Study 4: no description of TENS intervention given. Therapist present. All studies: 5 days/week, 6 weeks
Outcomes	t‐test Neuropsycological tests: Digit span: ns for studies 1 ‐ 4 Visual memory span: ns for study 1, ns study 2, p = 0.002 study 3, p = 0.004 study 4. 8/15 words test (15 word used only in study 1) Immed. recall: p = 0.03 study 1, ns studies 2‐4 Delayed recall: ns studies 1‐4 Recognition: p = 0.05 studies 1 & 2, ns studies 3 & 4 Face recognition: ns studies 1 & 4, p = 0.01 study 2, p = 0.04 study 3. Picture recognition: ns studies 1, 3 & 4, p = 0.001 study 2. Word fluency: p = 0.04 study 1, ns studies 2 & 4, p = 0.03 study 3 Behavioural observational scales: Beoordelingsschaal vor Oudere Patienten (BOP) Subscales Need of help: ns studies 1 & 4, p = 0.01 study 2, p = 0.04 study 3 Aggressiveness: ns Physical invalidity: ns studies 1, 3 & 4, p =0.02 study 2 Depressed behaviour: ns Mental invalidity: ns Inactivity: ns Behaviour inventory: ns studies 1, 3, 4, p = 0.03 study 2.
Notes	Poor/limited reporting of interventions and results. Authors imply that treatment effect was evaluated directly post‐treatment and 6 weeks later but only one set of results given. They note that "Analyses of the data obtained after 6 weeks without stimulation revealed that the majority of the treatment effects observed in the above‐mentioned studies disappeared." Consider excluding due to limitations of description of interventions and outcomes.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear