Professor Dirk De Ridder, a world-leading expert in tinnitus, is investigating the combined effect of ketamine and brain stimulation on tinnitus loudness and distress, as part of a new phase 1/2 clinical trial.
The aim of the study is to determine if low dose ketamine, through its effects on brain plasticity, is able to catalyze transcranial electrical stimulation, and reduce tinnitus severity as a result.
A total of 24 participants with chronic tinnitus will get a chance to receive treatment with the experimental drug/device combination therapy, at the University of Otago Dunedin School of Medicine, in New Zealand. The treatment will be delivered twice, 10 days apart.
Inclusion criteria: Adults aged between 18-70 years with constant subjective tinnitus and a grade of 3 or higher (considered “moderate to severe”) on the tinnitus questionnaire.
The trial (Registration number: ACTRN12621000119897p), titled “Effect of ketamine and concomitant multi-target high definition transcranial electrical stimulation on tinnitus loudness and distress in adults- A feasibility and safety study”, is registered prospectively on the Australia New Zealand Clinical Trials Registry.
As of May 12, 2021, it is unclear whether or not anyone has been enrolled (yet) or if the coordinators have begun recruiting participants.
The anticipated date of first enrollment is listed as February 15, 2021. However, according to the provisional study record, the trial’s ethics application is still awaiting approval.
Here is some more information, taken directly from the provisional study record (emphasis/formatting ours):
Ketamine and High Definition, Trancranial Infraslow Pink Noise Stimulation (HD-tIPNS)
The intervention arm will receive a low dose of subcutaneous ketamine (0.5mg/kg) as a bolus, from a clinician experienced in administration. This will be followed by HD-tIPNS administered for a single session of 30 minutes duration, beginning ~25 minutes after ketamine delivery, by a researcher experienced in administering neuromodulation techniques.
A battery-driven wireless 32 channel transcranial current stimulator (Starstim32 TCS®, Neuroelectrics) will be used to deliver stimulation while the participants are comfortably and quietly seated. Simulation [sic] is delivered by AgCl electrodes placed in the international 10-20 arrangement, secured in a neoprene cap (see Neuroelectrics website for headset image). For the active treatment group, the stimulation will be delivered at a current strength of maximum of 2mA for 30min, with 60s ramp up and ramp down at the beginning and end of each stimulation session, with continuous stimulation in between. For sham stimulation, to create an identical skin sensation to the active stimulation, the current will be applied for a 60s ramp up (0-2mA) and 60s ramp down (2-0mA) at the beginning and the end of each stimulation session, without any current for the remainder of the stimulation period.
This Intervention will be delivered twice, spaced 10 days apart. Intervention duration will be a total of 2 hours in length to allow for safety monitoring. After a 20 day washout, both groups will transition to the intervention, delivered twice again, 10 days apart.
The delayed start occurs as follows: Participants can be allocated to start with Ketamine + Active Stimulation or Ketamine + Sham Stimulation. Both the sham stimulation and the active stimulation groups will receive active stimulation after the 20 day washout (the Ketamine + Sham stimulation is the active control). Therefore the Ketamine + Sham stimulation (Active control) receives a delay to the start of active intervention.
Participants will undergo treatment at the Department of Psychological medicine laboratory at the Dunedin School of Medicine, University of Otago.
- Intervention  Treatment: Drugs
- Intervention  Treatment: Devices
Comparator / control treatment: Participants in the control arm will receive a low dose of subcutaneous ketamine (0.5mg/kg) as a bolus, from a clinician experienced in administration. This will be followed by Sham stimulation, designed to create identical skin sensations to active stimulation. Participants will use identical equipment to that of the active group, and will receive a short dose of the treatment protocol, mimicking the initial tingling/prickling commonly experienced with Transcranial electrical stimulation.
Tinnitus Functional Index (TFI). The TFI has eight subscales that address the intrusiveness of tinnitus, the sense of control the patient has, cognitive interference, sleep disturbance, auditory issues, relaxation issues, quality of life, and emotional distress. This provides an overall measure of how much of a problem tinnitus is for participants (severity).
- Adults aged between 18-70 years with constant subjective tinnitus and a grade of 3 or above on the tinnitus questionnaire.
- Minimum age 18 Years
- Maximum age 70 Years
- Gender Both males and females
This article will be updated as more information is added to the study record.
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