The somatosensory evoked response in patients with hysterical anaesthesia

https://doi.org/10.1016/0022-3999(73)90007-XGet rights and content

Abstract

The cortical somatosensory averaged evoked response (A.E.R.) was studied in nine patients with hysterical anaesthesia (eight with hemianaesthesia, one with “stocking” anaesthesia).

Stimuli were applied either to a peripheral nerve or to skin receptors and the stimulus intensity defined with reference to the threshold of the nerve action potential recorded further up the limb involved. The results were as follows:

  • 1.

    1. A.E.R.'s should be recorded in all patients even when they reported no subjective sensation.

  • 2.

    2. When the stimuli were applied to skin receptors the amplitude of the A.E.R. from the anaesthetic area was always smaller than that from non-anaesthetic area.

  • 3.

    3. When stimuli were applied to a peripheral nerve, the anaesthetic area produced a smaller A.E.R. with near-threshold stimuli but when the stimulus intensity was increased the two areas evoked A.E.R.'s of comparable amplitudes.

  • 4.

    4. In three patients tested after recovery these differences disappeared.

It is suggested that at least two separate physiological mechanisms may be involved in the mediation of hysterical anaesthesia, and that the technique may be useful both diagnostically and as a research tool.

References (7)

There are more references available in the full text version of this article.

Cited by (35)

  • Self-Awareness Disorders in Conversion Hysteria

    2015, The Neurology of Consciousness: Cognitive Neuroscience and Neuropathology
  • Psychogenic Unresponsiveness and Nonepileptic Seizures

    2008, Handbook of Clinical Neurology
    Citation Excerpt :

    Aggregate data from dexamethasone suppression/corticotropin-releasing hormone tests are used in depression and post-traumatic stress disorder research but do not reliably establish the diagnoses in individual patients (Baghai et al., 2002; Yehuda et al., 2004). Motor evoked potentials and somatosensory evoked potentials have been used in conversion paralysis and anesthesia, respectively, for assisting diagnosis in small case series (Levy and Mushin, 1973; Morota et al., 1994). Structural and functional neuroimaging reveal volumetric reductions and perfusion deficits in mood and anxiety disorders in aggregate data.

  • Hysterical conversion and brain function

    2005, Progress in Brain Research
    Citation Excerpt :

    On the other hand, a few other studies have reported subtle changes in paradigms that were slightly more sophisticated than just detection of simple tactile stimuli. For instance, tactile stimuli close to perceptual threshold may fail to produce normal evoked potentials in patients with sensory conversion symptoms, even when stimuli above threshold still produce normal responses (Levy and Mushin, 1973). In addition, anomalies in the rate of habituation to repeated stimulations were observed in hysterical conversion using SEPs (Moldofsky and England, 1975) as well as skin-conductance reactivity (Horvath et al., 1980).

View all citing articles on Scopus

From the Bethlem Royal and Maudsley Hospitals and The National Hospital for Nervous Diseases.

View full text