Rats administered chronic neuroleptics develop oral movements which are similar in form to those in humans with tardive dyskinesia

Oral movements (OMs) in rats chronically administered haloperidol (HAL), fluphenazine (FLU), or no drug were recorded using a computerized video analysis system which measured the distance between two fluorescent dots painted above and below the rat's mouth. The resulting data was analyzed using fast-fourier analysis. Following an initial period of sedation (decreased energy at all frequencies), the drugged animals (and especially the FLU animals) began to show increased oral movements of 1–2 Hz, an effect which increased substantially upon drug withdrawal. This is precisely the altered energy spectrum observed in humans with tardive dyskinesia.