For patients with schizophrenia, a shot of electricity could help with facial emotion recognition
June 2, 2015
Social cognition in schizophrenia
Social cognition in schizophrenia
Transcranial direct current stimulation, an experimental therapy that involves delivering electrical current to specific parts of the brain, could prove useful in improving social cognition in patients with schizophrenia. An international team of researchers tested the device, which is powered by a 9-volt battery, on 36 participants with schizophrenia and found that a single 20-minute session improved a patient's ability to recognize facial emotions—a trait commonly impaired in patients with schizophrenia. The results were published in Schizophrenia Research on April 29, 2015.
"Currently, there are two main symptom domains recognized in schizophrenia, positive and negative," says Dr. Walter Dunn, a fellow in the Mental Illness Research, Education and Clinical Center at the VA Greater Los Angeles Healthcare System. "Most people associate schizophrenia with positive symptoms, things like delusions and hallucination, but what is increasingly being recognized is that there are also neurocognitive and social cognitive deficits, things like memory and attention," says Dunn. "Social cognition includes skills we use in everyday interaction. People pick up cues from a person's facial expressions and voice modulation. You can tell if a person is angry, sad, interested, or bored. What's more, you can imagine what they might be thinking."
According to Dunn, also a clinical instructor at UCLA, social cognition deficits are actually a better predictor of how a patient with schizophrenia is faring than some of the more commonly thought-of symptoms. But while much of the treatment in recent decades has focused on the positive domain—such as antipsychotic medication to control hallucinations— there are no medications available for the treatment of cognitive symptoms.
Even the most effective treatment, cognitive remediation therapy, basically a set of cognitive drills, is only modestly effective at improving social cognition, says Dunn.
Dunn and his colleagues, from VA, UCLA and an Israeli university, drew on recent research showing transcranial direct current stimulation could be effective at improving brain function in a variety of settings, from stroke patients to those with epilepsy.
"The device is pretty straightforward," says Dunn. "It involves a direct current via two small electrodes placed on the scalp, an anode and a cathode. The current flows from one side to the other. Depending on which part of the brain is under the anode or the cathode, that part of the brain is either enhanced in excitability or decreased in excitability. So if you wanted to excite a part of the brain, you'd place the anode over that area, and vice versa if you wanted to decrease activity."
Transcranial direct current stimulation differs from transcranial magnetic stimulation (TMS), which uses a magnetic field produced by a coil that is placed near the head. The coil delivers a small electrical current to portions of the brain to get the neurons in those areas to fire. Transcranial direct current stimulation, on the other hand, delivers a small electrical current to change how excitable the neurons are. While this can occasionally cause neurons to fire, the effect is much more subtle and somewhat targeted. While both are commonly used in research, TMS has already been approved by the Food and Drug Administration for certain conditions.
Neither treatment should be confused with electroconvulsive therapy, formerly known as shock therapy, which aims to induce a seizure via a larger electrical current and is sometimes used as a last resort in treating major psychiatric illnesses.
Study compared treatment against placebo
For the study, the researchers divided the 36 participants into three groups. Twelve received anode stimulation to excite the pre-frontal cortex, a part of the brain potentially involved in social cognition. Twelve more received cathode treatment to decrease excitability in that part of the brain. The remaining participants were given a sham, or placebo, treatment.
After the procedure, each participant underwent a battery of social cognition assessments to include an emotional intelligence test, a facial emotion identification test, and a nonverbal sensitivity assessment. And while for the most part the participants' scores remained unchanged, those who underwent the anodal stimulation scored moderately better at facial emotion recognition.
"In the facial emotion recognition, participants are shown pictures of faces displaying a variety of emotions. They are then supposed to identify what emotion the person in the picture is displaying," says Dunn.
While Dunn would describe the effects as only a moderate improvement, it's also important to note that there was improvement after only one 20-minute session. Those effects, he said, could be expected to last for an hour or two after the treatment. There is research that suggests longer-term application, meaning more treatments over an extended period of time, could potentially condition the brain in such a way that benefits could be prolonged for up to several months after treatment stops.
The results add to a growing body of similar research, including a recent study by Dr. Tasha Nienow, a psychologist at the Minneapolis VA Health Care System, that suggests transcranial direct stimulation is also effective at improving working memory among patients with schizophrenia.
"Transcranial direct current stimulation is safe, it's portable, and it's relatively cheap," says Dunn. "It could prove to be a really valuable tool to treat patients with schizophrenia and could lead to a dramatically improved quality of life for these individuals."