Relationships of behavioral measures of frontal lobe dysfunction with underlying electrophysiology in cocaine-dependent patients.
OBJECTIVE
Despite evidence that frontal lobe functioning is impaired in cocaine-dependent individuals, relationships between behavioral measures of frontal dysfunction and electrophysiological measures of inhibition in cocaine use have not been explored.


METHODS
Using the Frontal Systems Behavior Scale (FrSBe), frontal dysfunction was assessed in a group of abstinent cocaine-dependent subjects (N = 49) and healthy controls (N = 32). Using transcranial magnetic stimulation (TMS) and evoked potential (EP)-based electrophysiological measures of inhibition, we assessed associations between these measures and FrSBe estimates of frontal dysfunction.


RESULTS
Patients had significantly higher FrSBe scores for executive dysfunction, disinhibition, and apathy than controls. Lower TMS-based resting motor thresholds (ie, hyperexcitability) were significantly associated with higher executive dysfunction scores in the patients.


CONCLUSIONS
Relationships between FrSBe scores and TMS-based measures highlight neurophysiological aberrations underlying frontal lobe dysfunction in cocaine abusers. TMS and EP measures may be useful probes of the intermediary steps between frontal lobe dysfunction and addictive behavior.
Department of Psychiatry and Behavioral Neurosciences, School of Medicine, Wayne State University, Detroit, Michigan.
Klevest
K
Gjini
Aisha
A
Qazi
Mark K
MK
Greenwald
Ravinder
R
Sandhu
Diane C
DC
Gooding
Nash N
NN
Boutros
D000328:Adult; D057565:Apathy / Q000502:physiology*; D016022:Case-Control Studies; D019970:Cocaine-Related Disorders / Q000503:physiopathology* / Q000523:psychology*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D056344:Executive Function / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008875:Middle Aged; D009433:Neural Inhibition / Q000502:physiology*; D009483:Neuropsychological Tests; D055139:Sensory Gating / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult