Protocol for Repetitive Transcranial Magnetic Stimulation with Symptom Provocation to Treat Obsessive-compulsive Disorder

We developed a protocol to standardize the implementation of the only FDA-cleared treatment with transcranial magnetic stimulation for obsessive compulsive disorder. Main challenges include translating protocols using research for regulatory clearance into everyday clinical practice and ensuring reproducible and safe delivery across multiple centers. Before treatment, the psychologist assesses the patient to construct the symptom provocation list that will be used during TMS stimulation.

When consulting the patient, first explain the rationale and procedure for symptom provocation and clarify any questions the patient may have. Administer the Yale Brown Obsessive Compulsive Scale Second Edition Symptom Checklist to identify active obsessions and compulsions. Next, create a draft list of primary symptoms including obsessions, compulsions, and avoidance behaviors.

Ask the patient to rate each symptom using the visual analog scale and record the scores next to each item. Collaboratively discuss and revise any ratings that appear inconsistent. Complete the clinician-rated Yale Brown Obsessive Compulsive Scale Second Edition severity scale based on the previous week, using the symptom list and other relevant information regarding the patient's functioning.

In collaboration with the patient, construct a symptom hierarchy from the primary symptoms list, selecting the most significant target symptoms for provocation that elicit moderate distress. Create a customized list of internal and external provocation stimuli based on the established hierarchy. Provide a concise summary of the patient's clinical history, highlighting the nature and severity of their obsessive compulsive symptoms.

Review the individualized symptom provocation list, including the specific internal and external provocations that will be used. Highlight annotations that indicate which items are especially effective and which should be avoided due to their potential to cause excessive distress. Provide clinical notes or contextual strategies to facilitate the smooth and effective delivery of provocations.

Ensure that the psychologist maintains communication with the technician throughout the treatment course. Instruct the technician to thoroughly review and become familiar with the content of the symptom provocation list before starting the first treatment session. Explain the treatment rationale for repetitive transcranial magnetic stimulation, or rTMS, expected sensations during stimulation, and possible side effects to ensure the patient feels comfortable and engaged.

Using a single low-intensity pulse, demonstrate the tapping sensation on the forearm to help the patient anticipate the experience if necessary. Then, place a lycra cap on the patient's head, aligning it with the patient's eyebrows and the apex of the helix on each ear to establish consistent reference points for future sessions. Now, provide a pair of earplugs to the patient to reduce auditory discomfort during stimulation.

To determine the motor hotspot, sit the patient comfortably with legs uncrossed and barefoot, with both feet either resting on a cushioned leg support or hanging freely. Then, using a measuring tape, trace the midsagittal line by measuring the distance from the nasion at the bridge of the nose to the inion at the raised area on the lower back of the skull. To identify the intertragal line, measure the distance between the left and right tragus, which are the small cartilage nubs in front of each ear canal.

The intersection of this line with the midsagittal line defines the cranial vertex, Cz, which will serve as the reference point. Position the coil just posterior to the Cz along the midline with the handle oriented posteriorly. For motor threshold determination, with the stimulator in single-pulse mode, deliver initial stimulation pulses at a low intensity to help the patient get used to the tapping sensation and assess tolerability.

Set the intensity to 50%of maximum stimulator output and deliver single pulses with an interstimulus interval of at least three seconds. Once a motor response is detected, deliver another pulse at the same location to confirm visible dorsiflexion of the foot. If foot dorsiflexion is confirmed, adjust the coil to identify the site that produces the strongest and most consistent visible contraction, defined as the leg motor hotspot.

To determine the leg resting motor threshold, mark the anterior edge of the coil on the patient's cap without moving the coil from the identified location to ensure accurate coil placement in future sessions. Gradually decrease the stimulation intensity in small steps to determine the lowest intensity that elicits visible muscle contraction in at least three out of five consecutive single pulses. Record this value as the leg resting motor threshold in the patient's file.

To identify the treatment site, using a flexible ruler or measuring tape, locate the treatment site by measuring four centimeters anterior to the motor hotspot along the sagittal midline. Mark the treatment site clearly on the patient's cap to serve as the coil placement reference for future sessions. For symptom provocation, start the symptom provocation procedure.

This should start with general questions about the patient's day to build rapport and gather contextual cues for guiding the provocations. Intentionally activate obsessive symptoms to enhance treatment efficacy. Aim to provoke a moderate anxiety level rated between four and seven on a 0 to 10 visual analog scale.

Instruct patients to refrain from engaging in compulsions or anxiety-reducing behaviors until the session concludes to maintain distress levels during the rTMS session. Use the symptom provocation hierarchy flexibly, starting with less anxiogenic items and gradually progressing toward more distressing provocations. As each provocation is delivered, ask the patient to rate their current anxiety on a visual analog scale from 0 to 10.

If present in the hierarchy, use external provocations such as instructing the patient to start a washing compulsion and interrupt it midway. Record the item from the provocation hierarchy that triggered the desired distress level. Start the TMS treatment by setting the treatment protocol on the stimulator to high-frequency stimulation and 100%of the leg motor threshold with 50 trains totaling 2, 000 pulses over approximately 18 minute.

Ensure the coil orientation aligns with the previously marked positioning, and hold the coil in place using either the mechanical arm of the TMS system or by manual positioning. Confirm with the patient that they are comfortable and that the earplugs are properly placed before beginning the session. Also verify that all technicians and individuals present in the room are also wearing hearing protection.

Inform the patient that the session is about to start. If the patient is unfamiliar with TMS or sensitive to stimulation, use ramping to reduce discomfort during the initial sessions. After confirming the coil's precise alignment over the treatment site, initiate the treatment protocol in the stimulator while ensuring accurate coil placement throughout the procedure.

Remind the patient to continue thinking about the provoking item to maintain an adequate level of obsessive compulsive distress during stimulation. Once stimulation concludes, carefully remove the coil, followed by the cap, and instruct the patient to take out their earplugs. Instruct the patient to stand up slowly, and observe them for any signs of dizziness or imbalance.

This protocol is based on the results of the pivotal randomized clinical trial published by Carmi et al. American Journal of Psychiatry 2019, that led to regulatory clearance of TMS for OCD. In this clinical trial, at week six of treatment, 38.1%of patients in the active treatment group achieved a full response, compared to 11.8%in the sham group, and 55%of patients in the active group showed a partial response, compared to 28%in the sham group.

This work fills the gap between regulation and daily clinical practice through a complete step-by-step protocol for delivering TMS for OCD. This protocol incorporates structured steps to develop and conduct individualized symptom provocation, as has been described in the research leading to clearance of TMS for OCD. Future research should focus on individualization of treatments, for example, through connectivity-based TMS targeting, expected to improve delivery precision and efficacy.