tDCS-enhanced Working Memory Training in Subjective Cognitive Decline

Effects and Mechanisms of Cognitive Control Training Combined With Transcranial Direct Current Stimulation (tDCS) in Subjective Cognitive Decline.

This 2-armed randomized, sham-controlled, single-blind study aims at providing evidence for the efficacy of a transcranial direct current stimulation (tDCS)-enhanced cognitive control training (PASAT) in participants with subjective cognitive decline (SCD). Overall, the study will include 30 participants. Each participant will take part in a four weeks training (12 sessions); 50% of the participants will receive 2mA anodal tDCS for 20 minutes applied to the left dorsolateral prefrontal cortex (dlPFC), the other half will receive sham stimulation. Event-related potentials (ERPs) evoked by the feedback on the correctness of the response at baseline and after training will be measured with EEG as neurophysiological signatures of cognitive control. Near and far transfer will be assessed by a verbal 2-back task and the Trail Making Test A and B. The amount of worrying regarding the memory impairment will be quantified by means of a 10 point Likert-Scale. Together with changes of PASAT performance these measures will be obtained before and after the tDCS-enhanced training. Follow-up assessments 3, 12 and 24 months after training will investigate the stability of training effects.

Sham Stimulation: Ramping up over 50 seconds at the beginning and an equal amount of time for tapering off at the end

DC-Stimulator MC, NeuroConn: 20 minutes of sham stimulation; Ramping up over 50 seconds at the beginning and an equal amount of time for tapering off at the end;

20 minutes of 2 mA anodal stimulation; Electrode placement: left dorsolateral prefrontal cortex (F3, EEG 10/20 system), return electrode at the right upper arm.

The amount of worrying regarding the memory impairment will be quantified by means of a 10-point Likert-Scale

Group comparison (active vs. sham tDCS) regarding the change in amount of correct answers in the PASAT task from baseline to end of training period.

Group comparison (active vs. sham tDCS) regarding the change in amount of correct answers in the verbal 2-back task (pre-session outcomes compared with post-session and follow-up outcomes).

Group comparison (active vs. sham tDCS) regarding changes in Trail Making Task A and B outcomes (pre-session outcomes compared with post-session and follow-up outcomes).

Group comparison (active vs. sham tDCS) regarding changes in Satisfaction With Life Scale outcomes (pre-session outcomes compared with post-session and follow-up outcomes).

Group comparison (active vs. sham tDCS) regarding changes in the Neuropsychological Test Battery CERAD-Plus (pre-session outcomes compared with follow-up outcomes).

Inclusion Criteria: Men and women, aged 60 years and above Native German speaker Subjective feeling of worsening cognitive abilities, including memory Present concerns regarding the subjective memory decline Right handedness Exclusion Criteria: Present objective cognitive impairment (Mini-Mental State Examination < 24) Current depression or depressive episode (Geriatric Depression Scale > 5) Current substance abuse Presence of other psychiatric disorders (MINI International Neuropsychiatric Interview) History of epilepsy Presence of other neurological disorders Absence of independent living skills (Instrumental Activities Of Daily Living, IADL) Scale) Metallic implants near the electrodes (i.e. pacemakers)