The investigators want to investigate the effect of rTMS on working memory measured by the N-back task. This is a single case experimental design, ABAB.

Rationale: The survival rate of patients after cardiac arrest and resuscitation has increased considerably. A common consequence of cardiac arrest is ischemic-hypoxic brain damage leading to cognitive impairment. Currently, there is a lack of knowledge regarding effectiveness of treatments to improve outcomes of patients with cognitive impairment after a cardiac arrest.

Objective: The primary objective is to investigate the effects of rTMS (iTBS protocol) on working memory of people with memory impairments after a cardiac arrest in the past Study design: This will be a single blinded replicated randomized SCED withdrawal designs study.

Study population: Nine adults who had a cardiac arrest in the past will be participating in this study. They are recruited in the general population.

Intervention: If participants are suitable based on the screening. Participants are invited to the university of Maastricht. There they receive intermitted theta burst stimulation with a TMS coil for 3 minutes on the dorsolateral prefrontal cortex. Then they perform the N-back task for 8 to 12 minutes to estimate working-memory performance. Then they have a break (45 min). Then they receive 3 minutes of sham stimulation after which they have to perform the N-back task again for 8 - 12 minutes. This will be repeated (active stimulation - sham - active stimulation - sham).

Main study parameter: The main study outcomes are performance on the N-back task with regard to accuracy.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The participant has to come to the university twice. The screening session takes approximately 1-1,5 hour, the experimental session 3,5 hours. The participant could experience side effects of the rTMS, these include: headache, scalp discomfort, tingling or twitching of the facial muscles, and light-headedness. Serious side effects are very rare, but they may include: seizures. The N-back task can be experienced as tiring.

Inclusion Criteria:

• Had a cardiac arrest between 3 months and 5 years prior to the experiment session.
• Scores lower than the general population (corrected for age, education, and sex) on at least one of the cognitive tests ( SD < -1 on the Stroop, digit span, or TMT).
• Age 18 up to and including 75.
• Proficient in Dutch or English to understand the instructions for the N-back task.
• Has sufficient understanding to perform the N-back task.
• Written informed consent

Exclusion Criteria:

• Has a pacemaker or ICD (implantable cardioverter-defibrillator)
• A history or a family member with a history of seizures / epilepsy (asked on the phone and checked on the first appointment).
• Metal implants in or near the head.
• Pregnancy
• Any other neurological disorder impending working memory performance besides the OHCA.

The participant won't be told if they receive sham or active stimulation.