Auditory Brainstem Response as a Diagnostic Tool in Schizophrenia and Bipolar Disorder

Background:

Within the daily clinical work of all medical specialties, objective diagnostic tools are paramount. However, in the psychiatric field such measures are lacking. Since 1983 the method of psychoacoustics has been under development in hope to serve this purpose. A recent development of auditory brainstem response (ABR/SD-BERA), has been proposed as a potential diagnostic tool within psychiatry.

The ABR is a diagnostic tool used primarily to diagnose sensorineural hearing loss. It detects evoked potentials, generated by neuronal activity in the auditory pathways in the brainstem, within the first 10 ms following acoustic stimulation. The potentials are recorded by surface electrodes placed on the forehead and on the mastoid processes. The wave pattern recorded consists of seven peaks, which are interpreted with respect to latencies and amplitudes.

Previous studies have aimed to associate the peaks with specific anatomical structures. The method SD-BERA is a further development of the standard ABR. It uses a wider array of acoustic stimuli, including complex sounds, for instance masking noises. The measuring procedure will roughly take 25 minutes. Previous studies using these complex sounds to compare mentally healthy subjects with patients suffering from schizophrenia, ADHD and bipolar disorder have shown that the different psychiatric groups exhibit specific wave patterns.

Aims

The aim of the first study is to validate previous results and identify five (n=5) patients with diagnosed ADHD, schizophrenia and bipolar disorder, and to compare these patients (n=15) with healthy, age-matched controls.

The aim of the second study is to present a blinded study where 12 patients with schizophrenia and 12 patients with bipolar disorder (total n=24) are compared to each other and to healthy controls (n=12) in order to evaluate the method as a diagnostic tool in clinical healthcare practice.

Inclusion criteria

• Best-practise diagnosed schizophrenia, bipolar disorder or ADHD
• Diagnosed since at least one year prior to enrollment.

Exclusion criteria

• Serious hearing loss
• Severe ongoing alcohol abuse or drug abuse
• Diagnosed psychiatric comorbidity
• Brain injury following cranial trauma