Temporal artery pulse amplitude wave shapes in migraineurs: a methodological investigation

This paper describes three atypical wave forms observed in temporal artery pulse amplitude recordings. Analysis of concurrent EMG records showed that two of these wave forms, spikes and spasms, were associated with muscle changes and may be regarded as artefacts. The third wave form, double peak, was not associated with EMG changes and may represent a local vascular dysfunction. Double peaks were observed to occur more frequently in migraineurs and specifically at the site of pain onset. Explanations for double peaks are discussed. It is concluded that they indicate a dysfunction in the regulation of vascular tonicity. This dysfunction is described as variable tonicity.

An experimental investigation of pain production in headache patients

An experiment was conducted to test two assumptions underpinning the prevailing medical model of tension headache: (1) that tension headache pain is due to sustained contraction of the skeletal muscles of the scalp; (2) that the muscle contraction produces greater pain for tension headache patients than for migraineurs. Six tension headache patients and six migraine patients were compared with six matched non-headache control subjects. All subjects used visual EMG biofeedback to hold different levels of frontalis muscle contraction for periods of one and three minutes. Ratings of pain and subjective tension were obtained for all trials. The results provided little support for either hypothesis. Pain ratings were not clearly related to induced EMG levels, but there was clear evidence that subjective tension was a function of EMG activity. It is suggested that the role of psychological factors in the production of pain should be further explored.

Partial reinforcement in human biofeedback learning

This paper reviews the evidence for the efficacy of partial reinforcement in producing resistance to extinction in human biofeedback experiments. The methodological criteria necessary to demonstrate such effects are discussed, as is the status of the analogy of reinforcement and information feedback. It is suggested that the problem of maintaining responding in the absence of feedback should be tackled empirically rather than assuming the validity of findings from other areas of learning theory.