'Hearing voices' is not a symptom restricted to patients with psychosis, physicians in Switzerland report. They describe a case illustrating how auditory hallucinations can occur when neurological conditions affect the parts of the brain used to process and monitor speech.

According to Dr. Daniela Hubl at the University Hospital of Psychiatry Bern and her associates, their patient was a 63-year-old, previously healthy woman, who suffered a traumatic brain injury caused by a bicycle accident that occurred in August, 2006.

As reported in the August 11th issue of The Lancet, MRI showed a "subarachnoid haemorrhage caused by a ruptured aneurysm of the left middle cerebral artery, and damage to a region encompassing part of the left frontal, temporal, and parietal lobes." On day three, the aneurysm was clipped and a decompressive craniotomy was performed.

The patient regained consciousness seven days after the injury, with right-sided hemiplegia and global aphasia, both of which responded to rehabilitation although she remained dysphasic.

In late October, her dysphasia worsened suddenly, and EEG indicated epilepsy. After treatment the dysphasia improved, though she still spoke with single words and short sentences.

In late December, the patient began having auditory hallucinations. She described them as "her own thoughts aloud, ...echoes of earlier conversations, (and) voices of the hospital staff commenting on things that had just happened."

She said that the voices sounded just like other voices, "except that they said only very simple and short sentences," similar to her own dysphasic pattern.

Because of recurring episodes of worsening dysphasia, the clinicians performed another EEG, which showed focal seizures in the left frontotemporal region. Once the patient's medications were switched to sodium valproate and levetiracetam, the hallucinations stopped, and there have been no recurrences by the time of her last visit in June, 2007.

According to Dr. Hubl and colleagues, their patient's experience with speech deficits that were the same as her own supports the hypothesis that auditory hallucinations "derive from inner speech that has been misidentified as coming from outside the self, because of defective monitoring."