Prefrontal Theta Burst Stimulation to Improve Cognitive Impairment After ICU Delirium: A Randomized Sham-Controlled Pilot Trial

Summary

Many older adults who survive a stay in the intensive care unit (ICU) experience delirium, a sudden change in attention and awareness caused by serious illness. Although delirium may resolve before hospital discharge, many survivors continue to experience ongoing problems with memory, attention, processing speed, and executive function (such as planning, organizing, and multitasking). These cognitive difficulties can interfere with daily activities and may increase long-term risk for cognitive decline. Currently, there are no proven treatments specifically designed to improve thinking and attention after ICU delirium. This study is testing whether a noninvasive form of brain stimulation called intermittent theta burst stimulation (iTBS) is safe, feasible, and potentially helpful for improving cognitive function in older ICU survivors who previously experienced delirium. iTBS is a patterned form of transcranial magnetic stimulation (TMS). It involves placing a magnetic coil gently against the scalp to deliver brief pulses of magnetic energy to a targeted region of the brain. In this study, stimulation is directed at the left dorsolateral prefrontal cortex, an area involved in attention, executive function, and cognitive control. The device used in this study is cleared by the U.S. Food and Drug Administration (FDA) for other conditions (such as depression), but its use for post-delirium cognitive impairment is investigational. This is a randomized, double-blind, sham-controlled pilot trial. Up to 40 community-dwelling adults between the ages of 50 and 75 who are approximately three months after an ICU stay with documented delirium will participate. Individuals with known dementia or certain neurological or psychiatric conditions are excluded to ensure safety and interpretability of results. Participation lasts approximately six weeks and includes 11 total visits: a baseline visit, 10 stimulation sessions over two weeks (five sessions per week), and a one-month follow-up visit. Each stimulation session lasts about 15-20 minutes. Cognitive testing is performed at baseline, immediately after the two-week stimulation period, and again one month later. The primary outcome measure is change in executive function, assessed using the Trail Making Test Part B. Additional tests measure attention, processing speed, language, and memory. The primary goals of this pilot study are to evaluate feasibility (ability to recruit and retain participants), safety, and tolerability of the stimulation protocol, and to estimate the magnitude of any cognitive changes. This study is not designed to establish definitive clinical effectiveness but to generate data to inform larger future trials. The broader goal of this research is to explore whether prefrontal neuromodulation could become a future strategy to promote cognitive recovery after ICU delirium.

Eligibility

Age range

50–75 years

Sex

All

Healthy volunteers

No

Interventions

• Device
  Intermittent theta burst stimulation

  Intermittent theta burst stimulation (iTBS) will be delivered using an FDA-cleared Brain Ultimate M-Series transcranial magnetic stimulation system. Stimulation will target the left dorsolateral prefrontal cortex (DLPFC), localized using the Beam F3 scalp-based method. Each session consists of 600 magnetic pulses delivered over approximately 3 minutes using a standard intermittent theta burst pattern (bursts of 3 pulses at 50 Hz, repeated at 5 Hz), administered at 120% of the participant's resting motor threshold. Resting motor threshold will be determined by visual confirmation of motor-evoked movement in the right abductor pollicis brevis muscle.

• Device
  Sham

  Sham stimulation will be delivered using the same Brain Ultimate M-Series transcranial magnetic stimulation system and figure-of-eight coil used in the active arm. The coil will be positioned at approximately a 45-degree angle relative to the scalp over the left dorsolateral prefrontal cortex (localized using the Beam F3 method) to minimize effective cortical stimulation while preserving auditory and tactile characteristics of active treatment.

Location