By MELANIE HSU
For The News-Letter
By MELANIE HSU
Schizophrenia severs one’s connection to reality by inhibiting perception of real voices, leaving the patient at the mercy of his or her inner voice. A research team at the University of Borgen recently elucidated the neural basis of these auditory hallucinations, using their findings to develop an electronic application that may help patients to better cope with schizophrenia’s symptoms.
According to Dr. Kenneth Hugdahl, auditory hallucinations appear very real to the schizophrenic, as if someone were standing in close proximity and speaking to the patient. At the same time, the patient is unable to hear the voices of people who are actually present.
What makes voices pathological has to do with the frequency of their recurrence. People tend to hear their names spoken in a crowd because the brain is primed to receive information that is of unique importance to the individual. Occasionally, the brain slips up and reconstructs unrelated sounds into a false perception of the person’s name. For the schizophrenic, however, the inner voices can be a recurring and relentless plague.
One of the most common symptoms of schizophrenia, auditory hallucinations, go beyond mistakenly hearing one’s name in a crowd. The hallucinations can manifest in a variety of ways, from a running commentary of a person’s thoughts to a voice ordering him or her to commit suicide. The powerful emotions experienced by some patients may increase the frequency of these verbal messages, leading to feelings of distress and helplessness.
Dr. Hugdahl and colleagues have attempted to better understand these hallucinations using a variety of neuroimaging techniques, including functional magnetic resonance imaging technology (fMRI). They found that in healthy patients, the perception of speech was accompanied by the spontaneous activation of neurons in the upper region of the left temporal lobe.
From these findings, Dr. Hugdahl theorized that neural activity in this area would be somewhat
increased, or even doubled, in schizophrenic patients. Instead, the team found that activity in the upper left temporal lobe ceased altogether in the presence of an inner voice.
Dr. Hugdahl and his colleagues, Kristina Kompus and Ren?? Westerhausen, followed up with a meta-analysis of 23 studies. The researchers looked at spontaneous inner-voice triggered neural activation in patients with schizophrenia or the stimulatory reaction prompted by actual sounds in healthy as well as schizophrenic subjects.
Through their examination, the researchers discovered that most papers reported either the perception of inner voices was accompanied by a spontaneous activation of neurons, or the patients’ perception of actual voices was suppressed when inner voices were simultaneously present. Hugdahl and his colleagues are the first to see the connection between these seemingly separate phenomena.
Further analysis revealed that one phenomenon was caused by the other; when neurons are activated by inner voices, the perception of outside speech is inhibited. This relationship exists because the preoccupied neurons are unable to properly process speech coming from the external environment. The findings may explain why schizophrenics lose touch with reality and close themselves off when experiencing hallucinations.
As further support for why schizophrenic patients become consumed by their inner voices, Hugdahl and colleagues found that the frontal lobe did not function normally in patients with schizophrenia. The result is poorer impulse control and an inability to block out hallucinations.
While everyone hears inner voices or melodies from time to time, non-schizophrenic patients are better at tuning out these internal voices. To help patients learn to suppress their inner voices, Dr. Hugdahl’s team developed an application for mobile phones and other simple electronic devices. The application broadcasts simple speech sounds via headphones and plays different sounds in each ear. The patient must learn to hear the sound in one ear while blocking out the sound in the other.
So far, the application has been tested on two patients with schizophrenia. The results are promising; while the voices are still there, the patients report feeling that they have more control over the voices. The patients are able to actively shift their focuses from the inner voices to external sounds, a possible breakthrough in the treatment of schizophrenia.