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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
40
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.
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.
University of Florida Shands Hospital
Gainesville, Florida, United States
RECRUITINGTrails Making Test B
Time (in seconds) required to complete Part B. Lower scores indicate better executive functioning. There is no fixed maximum score; the test is typically discontinued at 300 seconds. Range 0-300 seconds.
Time frame: From enrollment to one-month after the final TMS session
Trails Making Test A
Time (in seconds) required to complete Part A. Lower scores indicate better processing speed. Maximum allowable time: 300 seconds.
Time frame: From enrollment to one-month after final TMS session
Psychomotor Vigilance Task
Time frame: From enrollment to one-month after final TMS session
Digit Symbol Coding
Total number of correct symbols completed in 120 seconds. Range: 0-135 (depending on version). Higher scores indicate better processing speed.
Time frame: From enrollment to one-month after final TMS session
Controlled Oral Word Association Test
Total number of correct words generated in 60 seconds. Range: 0 to unlimited. Higher scores indicate better verbal fluency.
Time frame: From enrollment to one-month after final TMS session
Semantic Verbal Fluency Test
Total number of correct category exemplars generated in 60 seconds. Range: 0 to unlimited. Higher scores indicate better performance.
Time frame: From enrollment to one-month after final TMS session
Hopkins Verbal Learning Test
Hopkins Verbal Learning Test - Revised (HVLT-R). Total recall score across three learning trials. Range: 0-36. Higher scores indicate better verbal learning. Delayed recall: Range: 0-12. Higher scores indicate better memory retention.
Time frame: From enrollment to one-month after final TMS session
Logical Memory 1 and 2
Logical Memory 1: 0 to 50 (maximum raw score depends on scoring criteria; confirm exact maximum with manual - typically 50 units). Higher scores indicate better immediate verbal memory. Logical Memory 2: Score range: 0 to 50 (same unit structure as LM I). Higher scores indicate better delayed verbal memory.
Time frame: From enrollment to one-month after final TMS session
Craft Story 21 Recall
Score range: 0 to 44 Directionality: Higher scores indicate better verbal episodic memory.
Time frame: From enrollment to one-month after final TMS session
Montreal Cognitive Assessment Test
Total score range: 0-30. Higher scores indicate better global cognitive function
Time frame: From enrollment to one-month after final TMS session
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