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Middle ear muscle activity (MEMA) in schizophrenia using a noninvasive technique
1Psychiatry Service, Department of Veterans Affairs Medical Center, Palo Alto, California 94304, USA.
Abstract:
Rapid eye movement (REM) sleep middle ear muscle activity (MEMA) was recorded in four diagnostic groups: schizophrenics (n = 18), schizoaffectives (n = 8), depressives (n = 11) and healthy, nonpsychiatric controls (n = 10). Previous work suggested that schizophrenics have higher than normal rates of REM sleep MEMA; this previous study employed the MEMA recording technique of impedance audiometry, which involves a 90-dB stimulus probe tone. The present study, which utilized a silent, pressure-sensitive transducer (i.e. no acoustic stimulus), was undertaken to determine if the stimulus tone might have elicited excess MEMA in the schizophrenics. In this present study, we observed no significant differences in REM sleep MEMA among the four diagnostic groups, suggesting that REM sleep MEMA cannot be used as a biological marker to differentiate clinical disorders. This failure to replicate our previous finding of high MEMA rates in schizophrenics is likely due to sampling error; alternatively, high REM sleep MEMA rates might be elicited in a subgroup of schizophrenics with an acoustic stimulus.
Insights
Middle ear muscle activity during rapid eye movement (REM) sleep was studied in psychiatric patients and controls. No significant differences in REM sleep MEMA were found, suggesting it is not a reliable biological marker for these disorders.
Area of Science:
- Neuroscience
- Sleep Medicine
- Psychiatry
Background:
- Previous research indicated elevated middle ear muscle activity (MEMA) during rapid eye movement (REM) sleep in individuals with schizophrenia.
- The prior study utilized impedance audiometry with a loud acoustic stimulus (90-dB probe tone).
Purpose of the Study:
- To investigate if the acoustic stimulus in previous MEMA recordings influenced findings in schizophrenic patients.
- To determine if REM sleep MEMA can serve as a biological marker to differentiate between schizophrenia, schizoaffective disorder, depression, and healthy controls.
Main Methods:
- Middle ear muscle activity (MEMA) during REM sleep was recorded using a silent, pressure-sensitive transducer.
- Four groups were studied: schizophrenics (n=18), schizoaffectives (n=8), depressives (n=11), and healthy controls (n=10).
Main Results:
- No statistically significant differences in REM sleep MEMA were observed among the four diagnostic groups.
- The findings did not replicate previous reports of higher REM sleep MEMA rates in schizophrenics.
Conclusions:
- REM sleep MEMA, measured without an acoustic stimulus, does not appear to be a reliable biological marker for differentiating schizophrenia, schizoaffective disorder, or depression.
- The lack of replication may be due to sampling error or the possibility that acoustic stimuli elicit MEMA in a specific subgroup of schizophrenic patients.