Brain Computer Interface for Communication in Ventilated Patients

BACKGROUND

An inability to consistently and effectively communicate their most fundamental physical needs is a major problem for mechanically ventilated ICU patients. Patients rate about 40% of communication sessions as difficult and more than a third of communications about pain as unsuccessful. Nurses initiate about 86% of all communication exchanges as it is typically very difficult for a voiceless ICU patient to initiate communication. Patients in the ICU therefore commonly suffer unrecognized pain and discomfort, feelings of loss of control and insecurity, depersonalization, anxiety, sleep disturbances, fear and frustration. Caregivers also frequently report feeling anxious and frustrated in not being able to adequately assess the needs of their patients. This inability to communicate effectively can lead to the inappropriate use of sedatives and prolongation of time spent on the ventilator, which may then lead to increased ICU length of stay and costs. Furthermore, the inability to communicate with caregivers hampers the ability of critically ill patients to be active participants in their treatment and in decision-making, including decisions to withdraw or withhold life-sustaining treatment.

The use of picture boards with icons representing common patient needs and complaints (pain, fear, hot/ cold, thirst, bedpan etc) has been shown to improve nurse-patient communication for patients in the postoperative period on the ventilator. These picture boards are widely available in most ICUs and are the closest thing to a current standard for communication with voiceless mechanically ventilated patient, for the purposes of addressing fundamental physical and emotional needs. Recent pilot studies have described the use of computer-assisted communication using touch sensitive screens, eye blink detectors and gaze trackers to enable communication in the ICU patient. The majority of patients and hospital staff surveyed in these studies indicated that the use of a computer-assisted communication device improved the ability to respond to patient needs and address patient comfort. Gaze and eye blink tracker systems are expensive, however, while touch sensitive screens may not be suitable for the many ICU patients with weakness and restriction in motor ability. Patients in the ICU, particularly those with neurological illness, frequently suffer from significant weakness and loss of co-ordination, however, limiting their ability to use their arms and hands to indicate the appropriate item on the board. While patients in the neuroICU are frequently weak because of focal brain injury, about a quarter of patients requiring mechanical ventilation in other ICUs may have significant weakness from critical illness neuropathy and myopathy, limiting their ability to use their hands to select the appropriate icon on a picture board. There are several patient populations, however, for whom the use of a picture board or touch screen is impossible, including patients with high spinal cord injury, advanced ALS and brainstem stroke, who are voiceless, but also typically have no useful motor function of their limbs. These patients are "locked-in", to varying degrees, awake and alert but with no control of bodily function or ability to articulate and communicate using standard forms of communication.

The use of Brain Computer Interface (BCI) devices to facilitate communication in "voiceless" patients has recently generated interest. A BCI translates deliberate, voluntary modulation of cerebral electrical activity, typically recorded by electroencephalography (EEG) into computer commands. A variety of BCI devices have been used to permit patients with advanced Amyotrophic Lateral Sclerosis (ALS), high spinal cord injury and brainstem stroke with the locked-in-syndrome, who have no voluntary use of their limbs, to communicate to varying degrees. These devices have typically been evaluated in the rehabilitation setting, following the period of acute medical illness, or at home. No study has evaluated the use of a BCI device to assist with communication of the typical physical and emotional needs/ complaints of the critically ill. This is significant, not only for patients with spinal cord injury and stroke, most of who are initially admitted to an ICU, but to the potentially large number of ICU patients who cannot use a picture board or other finger contact system because of critical illness neuropathy/ myopathy or acute brain injury causing weakness. Our focus is on creating a steady state visual evoked potential (SSVEP) based, wireless BCI system to facilitate communication with intubated ICU patients., The wearable BCI device of interest in this study functions through visual attention to illustrative icons displayed on an electronic screen. The icon, which may depict a common ICU patient need, such the need for repositioning or common patient complaint, such as pain, can be displayed as a symbol. The patient can, thereby, communicate by looking at a specific item depicting their need or complaint. This wearable device is entirely noninvasive and without significant risk to patients, functioning only to record and translate EEG signals. The device will communicate wirelessly with the user interface (UI) that can be either a tablet or the flat screen TV monitor that is present in every ICU patient room. The proposed prototype provides a user interface that includes basic functions that are typically used in communication between nurses and patients in the ICU.

STUDY DESIGN

This is a translational pilot study of a Steady State Visual Evoked Potential (SSVEP) based BCI system to facilitate communication in intubated patients. After obtaining informed consent from the patient or their legally authorized representative, 30 patients will be recruited from the medical, surgical, cardiac, cardiothoracic and neurological intensive care units at the University of Michigan, Ann Arbor over a period of 12 months. Approval has been obtained from the Institutional Review Board of the University of Michigan (HUM00095052).

Screening for delirium and ability to participate in the study:

Potential subjects will be identified by members of the primary ICU team, who will then contact a study investigator. Subjects will need to be off all sedating medicines with return to full wakefulness prior to further evaluation. Patients meeting the above eligibility criteria who consent to participate in the study will then undergo further testing by an investigator to confirm that the patient is sufficiently alert and attentive to communicate AND is capable of consistently selecting items through volitional finger contact. The patient will then undergo a screening evaluation with the BCI device to confirm that their individual EEG signal can be detected and interpreted by the device.

Patient complaints/ needs: The investigators will evaluate the ability of subjects to accurately select a specific need or complaint from 10 common needs/ complaints.

1. "I am in pain"
2. "I have difficulty breathing"
3. "I need to be suctioned"
4. "I need to have a bowel movement"
5. "I need to pee/ pass urine"
6. "I am thirsty"
7. "I am hungry"
8. "I need to have my position in bed changed"
9. "Raise the head of my bed"
10. "I need my family at my bedside"

Picture board: Feasibility of communication using the BCI device will be evaluated using a picture board with illustrative icons representing the 10 needs/ complaints above as the standard for comparison and to determine the accuracy of selection of the appropriate icon. The icons and phrases on the picture board will be identical to the icons and phrases on the BCI device

SPECIFIC AIM 1:

To demonstrate the feasibility of using a Steady State Visual Evoked Potential (SSVEP) based Brain Computer Interface (BCI) device to facilitate communication of common patient needs in alert mechanically ventilated patients in the Intensive Care Unit (ICU).

Hypothesis 1: At least 80% of alert mechanically ventilated patients will be able to accurately select the illustrative icon on the brain computer interface representing the physical or emotional need self-identified by the patient as being the most common trigger for communication with the bedside nurse during their admission.

Orientation to BCI and picture board: The patient will initially be familiarized with both the picture board and the BCI device. Instruction on use of the BCI device will include demonstration of the UI, explanation of the icons on the UI and the mechanism of selection of an icon, through focused visual attention.

Selection of need/ complaint: Immediately following orientation, testing for accuracy of the BCI device will be performed. Testing for accuracy will be performed a single time for each patient, using the most important need/ complaint for that patient. The patient will be asked to identify on the BCI UI the specific need or complaint as being the most common reason to request the assistance of the bedside nurse during their admission, among the 10 patient need/ complaint options provided. Selection of "None of the above/ Other" will be permitted, however, the patient will be specifically instructed in advance to select the need/ complaint most applicable to their situation among the 10 choices provided. The patient will then be asked to select the SAME need/ complaint on the picture board using finger contact.

SPECIFIC AIM 2:

Specific Aim 2: To determine patient, family and bedside nurse satisfaction with communication using the BCI device and elicit open-ended feedback to guide future device improvements.

Hypothesis 2: At least 70% of patients will "agree" or "strongly agree" with the statement "The Brain computer interface device allowed me to communicate my needs to the bedside nurse adequately".

Immediately following evaluation of accuracy described under Specific Aim 1, the investigators will evaluate patient, family and bedside nurse satisfaction following bedside use of the device as the primary communication tool for 2 hours a day for 3 consecutive days. A delirium screen using CAM-ICU and a brief neurological examination to confirm the patient's ability to effectively use the BCI device and picture board will be performed prior to use of the device or picture board on subsequent days (days 2 and 3).

At the end of the 3 days, the patient, any family members present and each nurse who participated in testing will be provided the short questionnaires. The patient questionnaire with options will be read out to the patient.

Statistical Analysis:

The proportion of patients who pass Step 2 of screening who then also pass Step 3 will be calculated with exact binomial 95% confidence intervals. A proportion of at least 70% passing Step 3 of screening will be the initial threshold for feasibility, based on clinical estimates of value. The median time, with interquartile range, required for orientation to the BCI device and to the picture board will be calculated, and comparison performed using the Mann Whitney U-test. The proportion of patients who select the same icon on the BCI UI and the picture board will be calculated, with exact binomial 95% confidence intervals. In determining the accuracy of using the BCI device, a binomial analysis including multiple studies of BCI estimated the chance level at 63% (α = 0.05, 60 trials). Based also on a clinical estimate of what would be a minimum useful level of accuracy for a communication device, the threshold for accuracy in our study will be at least 80% of patients demonstrating concordance between selection of their most important need/ complaint on the BCI device and the picture board. Descriptive statistics will be used to for proportions of patients selecting responses to each of the satisfaction questions.