Stuttering, emotions, and heart rate during anticipatory anxiety: a critical review
Section snippets
The autonomic nervous system
The ANS controls the visceral functions of the body, such as the contractions of the heart, constriction of blood vessels, blood pressure, digestion, and sweating. The ANS consists of two major subdivisions, the sympathetic and the parasympathetic systems, which cooperate to adapt the bodily functions to different situations and demands (Guyton & Hall, 1996). In many autonomic functions, but not all, the sympathetic and parasympathetic systems have opposite effects, like acceleration versus
The freezing response: biological background
From an evolutionary perspective emotions can be seen as sets of genetically determined responses which are important to solve specific problems, like avoiding danger, finding food and reproducing. Each emotional state is associated with a specific way of reacting and behaving and the nervous system adapts the organism to the demands of the current situation. Both animals and humans show two contrasting behavioral expressions of fear. One is to freeze and become mute, and the other is to become
Autonomic activity in persons who stutter
Two of the most thorough studies of autonomic reactions in persons who stutter were made by Peters and Hulstijn (1984) and Weber and Smith (1990). Peters and Hulstijn measured skin conductance, pulse volume, and heart rate in 24 persons who stuttered and in 24 persons without speech problems. The measurements were taken before, during, and after tasks like mirror writing, intelligence test, reading aloud, and spontaneous speech. Contrary to what may have been expected, the stuttering group did
Alternative explanations of reduced heart rate?
As mentioned above, Obrist et al. (1965) observed reduction of heart rate and increase of vagal activation during anticipation of conditioned unpleasant stimuli. Obrist et al. discussed how this observation could be interpreted, with the basic assumption that vagal responses are not related to emotions like anxiety. Suggested mechanisms like “conditioned pressor response”, respiratory changes, or “orienting response” were found not to be congruent with the observations.
In persons who stutter it
Discussion
The reviewed psychophysiological studies of stuttering suggest that many adults who stutter tend to react with anticipatory anxiety and autonomic coactivation in stressful speech situations. This type of autonomic reaction is characteristic of a freezing response, which implies some degree of inhibition of motor activity and vocalisation. As mentioned above, a possible relation between the freezing response and stuttering was suggested by Peters and Guitar (1991). They proposed that observed
Acknowledgments
This article has been supported by grants from the Swedish Council for Research in the Humanities and Social Sciences, the Crafoord Foundation, and the Royal Physiographic Society. I wish to thank Jarl Risberg for valuable advice and review of manuscript, Charles Beck, University of Alberta, who was instructor for a paper that was the starting point for this article, Björn Folkow, Gothenburg University, for information regarding the physiology of freezing, Deborah Kully, University of Alberta,
References (30)
The periaqueductal gray and defensive behavior: Functional representation and neuronal organization
Behavioural Brain Research
(1993)- et al.
A new method for aversive Pavlovian conditioning of heart rate in rhesus monkey
Physiology and Behavior
(1996) - et al.
Comparison of peripheral blood flow patterns associated with the defense reaction and the vigilance reaction in rabbits
Physiology and Behavior
(1994) - et al.
Conditioned fear-induced tachycardia in the rat: Vagal involvement
European Journal of Pharmacology
(1998) - et al.
Stuttering and anxiety: The difference between stutterers and nonstutterers in verbal apprehension and physiologic arousal during the anticipation of speech and non-speech tasks
Journal of Fluency Disorders
(1984) - Berlinsky, S. L. (1954). A comparison of stutterers and non-stutterers in four conditions of experimentally induced...
- et al.
Heart rate variability: Origins, methods, and interpretive caveats
Psychophysiology
(1997) - et al.
Autonomic determinism: The modes of autonomic control, the doctrine of autonomic space, and the laws of autonomic constraint
Psychological Review
(1991) - et al.
Antipredator defensive behaviors in a visible burrow system
Journal of Comparative Psychology
(1989) - Bloodstein, O. (1995). A handbook on stuttering (5th ed.). San Diego, California:...