Introduction
Auditory hallucinations are a common symptom of psychotic disorders and are often refractory to treatment with 25% of patients being nonresponsive to standard therapy (Shergill et al. Reference Shergill, Murray and McGuire1998). Command hallucinations with homicidal and suicidal content create particularly difficult and dangerous cases (McNiel et al. Reference McNiel, Eisner and Binder2000). Here, we describe our experience with the use of bilateral tinnitus sound generators for augmentation in treatment-resistant auditory hallucinations. Tinnitus sound generators are similar to hearing aids in appearance and direct noise into the wearer's ears in attempt to attenuate the bothersome nature of tinnitus.
Case
The patient is a 31 year-old African-American female with five year history of schizoaffective disorder, bipolar type. She suffered from intense egodystonic command suicidal and homicidal auditory hallucinations with ideations resulting in frequent and prolonged psychiatric hospitalisations causing significant psychological distress. Her hallucinations were two loud male voices with continued negative commentary, pausing only for minutes and commanding the patient to kill herself and others with a mean score of 40/50 on Auditory Hallucinations Rating Scale (AHRS). The patient had been trialed on risperidone, quetiapine, aripiprazole and olanzapine at appropriate doses and durations without significant improvement in her auditory hallucinations, thus prompting initiation of clozapine. The clozapine was discontinued due to non-adherence and inability to achieve therapeutic blood levels. She was then transitioned to paliperidone palmitate monthly injections titrated to 234 mg once a month but without any significant change in her auditory hallucinations. Mood stabilisers including divalproex and lamotrigine had been previously attempted but discontinued due to intolerance. Transcranial magnetic stimulation (rTMS) had been unsuccessfully attempted previously, with the goal of reducing the presence of auditory hallucinations.
The patient was observed listening to loud music which she purported helped in the alleviation of auditory hallucination awareness. The first and senior authors have made similar observations among other psychotic patients with auditory hallucinations and this has been examined in a single study with beneficial outcomes (Na & Yang, Reference Na and Yang2009) among patients with schizophrenia. A single case series (Kaneko et al. Reference Kaneko, Oda and Goto2010) of two patients with schizoaffective disorders with auditory hallucinations were successfully treated with sound therapy using white and pink noise delivered by sound generators. Noise was utilised in lieu of music due to the possibility of negative emotional associations. Given these previous studies, an audiological consultation was initiated in which the patient's auditory system was determined to be within normal limits and was then fitted with bilateral tinnitus sound generators. At one week follow-up, the patient subjectively reported a 30% reduction in the intensity of hallucinations and reported high satisfaction, recommending consideration of tinnitus sound generators for others. These effects remained at the three month follow-up. Data from the devices showed an average of 15 hours daily use. Functional review showed improvements in several domains including improvement in concentration and the ability to read, something she had not done for over five years. She also showed successful behavioural activation with a new exercise regimen resulting in 22 lbs weight loss over a four month period on adjunct metformin. However, her follow-up AHRS and patient health questionnaire (PHQ-9) did not change from baseline. The patient required one seven-day hospitalisation during this period after a significant life transition which included discharge from active duty military service and new group home settings. At her last follow-up, continued use of tinnitus sound generators was reported and she was beginning to apply for jobs through vocational programs. She also began attending university.
Discussion
This is the third case of the use of tinnitus sound generators for auditory hallucinations in the literature. There are two prior reports of resolution of treatment-resistant auditory hallucinations in patients with schizoaffective disorders at one month follow-up, maintained at 17 and 31 months (Kaneko et al. Reference Kaneko, Oda and Goto2010). In the previous cases, the authors reported using white noise and subsequently switching to pink noise due to patient comfort. In our case, there was a subjective decrease of 30% in the intensity of auditory hallucinations without changes in frequency. In this case, we attempted to target the patient's positive symptoms of auditory hallucinations. However, the negative symptoms of psychotic disorders and the resulting deficits cause an even greater impact on quality of life (Green, Reference Green1996). In our case, it appears that there was greatest improvement in the domain of cognition likely due to improved attention and focus following reduction in her auditory hallucinations. The sole contribution of the tinnitus sound generators in her significant functional gains is unclear given other concurrent standard therapies such as cognitive-behavioural therapy, enhanced adherence due to depot antipsychotic injection. However, this case clearly illustrates tolerability of tinnitus sound generators based on the objective data from the devices which averaged 15 hour daily use despite our patient's history of non-adherence. Our proposed mechanism of action for these improvements and subjective auditory hallucination reduction was due to the attenuation effects of the pink noise. Acoustic stimulation with white noise has been noted to result in activity in the auditory cortex with residual inhibition, a phenomenon that is very similar to rTMS (Musiek et al. Reference Musiek, Ballingham, Barry, Paulovicks, Swainson, Tyler, Vasil and Weihing2007). The latter has been used to target auditory hallucinations and a recent meta-analysis showed a treatment effect size of 0.37 for negative symptoms (Vercammen & Aleman, Reference Vercammen and Aleman2009). Neither noise attenuation due to the presence of a tangible, external sound source or auditory cortical activation and inhibition however fully explain improvements noted in the two previously reported cases due to delayed onset of symptom relief and maintenance of effect after discontinuation of tinnitus sound generators. It is possible that tinnitus sound generators have multiple effects, but this is currently not fully understood.
Conclusion
Tinnitus sound generators have been shown to have a positive role in targeting treatment resistant auditory hallucinations in two prior reports. Our patient had a positive response with great tolerability, and satisfaction with the intervention. There appears to be a greater positive impact on cognitive symptoms with improved attention and focus. Given the benign nature of tinnitus sound generators, it presents an opportunity for future research to further elucidate their efficacy in treatment of auditory hallucinations, an area that is clearly in need of more effective approaches.
Declaration
This case was previously presented as a poster presentation at the 166th Annual Meeting of the American Psychiatric Association (San Francisco, May 2013). The views expressed in this case report are those of the author and do not reflect the official policy of the Department of Army/Navy/Air Force, Department of Defense or US Government.
