From the Guidelines
For a patient presenting with first-time auditory hallucinations, I strongly recommend an MRI (Magnetic Resonance Imaging) of the brain as the initial neuroimaging study, as suggested by the American Psychiatric Association Practice Guidelines for Treatment of Patients with Schizophrenia, second edition 1. This approach is based on the understanding that while the yield of neuroimaging in detecting pathology responsible for psychotic symptoms is low, especially in patients without neurologic deficits, MRI provides superior soft tissue resolution and can help identify potential organic causes of hallucinations such as tumors, strokes, inflammatory conditions, or neurodegenerative processes. Key points to consider in the management of such patients include:
- The low yield of CT scans in detecting significant pathology in patients with new onset psychosis and no neurologic deficit, ranging from 0% to 1.5% 1.
- The preference for MRI over CT scans due to its ability to provide detailed structural information, as suggested by the American Psychiatric Association Practice Guidelines 1.
- The importance of conducting a comprehensive psychiatric evaluation simultaneously with the neuroimaging study, as many cases of auditory hallucinations are related to psychiatric conditions rather than structural brain abnormalities.
- The consideration of alternative imaging modalities, such as CT scans, if MRI is contraindicated or unavailable, but with the understanding that MRI is the preferred initial study due to its superior diagnostic capabilities 1.
From the Research
Brain Scan Indications for Auditory Hallucinations
- There are no specific studies that directly indicate a particular type of brain scan for patients presenting with first-time auditory hallucinations.
- However, studies have used various neuroimaging techniques, such as functional MRI (fMRI) 2, 3, 4, to investigate the neural mechanisms underlying auditory hallucinations.
- These studies suggest that auditory hallucinations are associated with changes in brain structure and function, particularly in the left temporal lobe 3 and the default mode network (DMN) 4.
- fMRI has been used to study the effects of antipsychotic medication on brain activation in patients with auditory hallucinations 2, and to investigate the neural correlates of ongoing auditory hallucinations 3.
- Real-time fMRI neurofeedback has also been used to reduce auditory hallucinations and modulate resting state connectivity of involved brain regions 4.
Key Findings
- Auditory hallucinations are not synonymous with having a psychotic disorder, and may be caused by various factors, including borderline personality disorder, post-traumatic stress disorder (PTSD), hearing loss, sleep disorders, or brain lesions 5.
- The phenomenological features of auditory verbal hallucinations vary in different psychiatric disorders, and are associated with changes in specific brain structures and disturbances in brain function, blood flow, and metabolism 6.
- Interventions for auditory hallucinations include antipsychotic drugs, neurostimulation, and cognitive behavioral therapy 6.
Neuroimaging Techniques
- Functional MRI (fMRI) has been used to study the neural mechanisms underlying auditory hallucinations 2, 3, 4.
- MRI morphometry has been used to investigate grey matter density in the left peri-Sylvian region in hallucinating patients 3.
- Real-time fMRI neurofeedback has been used to reduce auditory hallucinations and modulate resting state connectivity of involved brain regions 4.