Background and history of the interface between anxiety and vertigo

Abstract

The comorbidity of vertigo and anxiety has been an integral component of the medical literature since antiquity. In the works of Plato, the same terms were used in the context of vertigo, inebriation, height vertigo, disorientation, and mental confusion. In classical medicine, vertigo had the ambiguous status of being both a disease per se and a symptom of other diseases such as hypochondriacal melancholy. Further, two etiologies were described for vertigo: an origin in the head (brain) and an origin in the hypochondria (abdominal viscera). In the course of the development of a detailed neurologic taxonomy of vertigo in the latter half of the nineteenth century, a debate ensued whether agoraphobia was a form of vertigo or a distinct psychiatric condition. Elucidation of this forgotten debate, within its historical context, provides insights into the recent rediscovery of the balance–anxiety interface.

Introduction

Awareness of the intellectual history of biomedical science serves three important purposes. First, an appreciation of history leads to a balanced perspective about the evolution of ideas, which produces a sense of humility about the role of our own ideas in an evolving intellectual corpus. Secondly, and trivially, it safeguards against expending excessive effort on rediscoveries. Thirdly, and fundamentally, the study of primary source material across millennia is the quintessential form of cross-cultural study. If key features of phenomena, considered currently as neurologic and psychiatric, are inexorably linked across two millennia from radically different intellectual perspectives, then one is confident that these phenomena are fundamental to human experience. Such is the case with the interface between balance disorders and anxiety. This interface will be developed along two main themes. First, there has been a linkage between vertigo and affective symptoms since antiquity. Second, vertigo was defined as a neurologic disorder in the mid-nineteenth century, and agoraphobia initially had an ambiguous status as a neurologic or psychiatric disorder. However, the enduring link between vertigo and agoraphobia is situationally specific dizziness.

Equilibrium is not one of the classical five senses (sight, hearing, smell, taste, and touch) that were enumerated by Aristotle in De Anima (McKeon, 1973, p. 70). Unlike the classical senses, which can be attributed to functions of specific sense organs, there is no single sense organ that we can identify consciously and intuitively as the source of normal sensations of movement and balance. However, since the consequences of disordered balance are obvious, balance can be viewed as a latent factor (or implicit sense) in virtually all daily activities. Further, the signs and symptoms that accompany dizziness or vertigo (e.g., unsteady gait, oscillopsia, palpitations, nausea, and vomiting) can readily be attributed to specific organs (e.g., central nervous system, muscle weakness, eyes, or visceral receptors). These signs and symptoms can be conceived as referred somatic and visceral manifestations of vestibular dysfunction (Balaban, 1999). Finally, the hidden nature of our sense of balance is preserved by plastic mechanisms in the central nervous system, which have a remarkable capability to compensate for disordered balance. Within this framework, the anxiety and situational avoidance that characterize space and motion discomfort may be a compensatory strategy that has the normal function of preventing exposure to potentially dangerous situations. As we shall see, height vertigo is a prominent example of situational discomfort and avoidance that is cited repeatedly in the historical literature.

Four specific terms for subjective vertigo are found in classical Greek texts: ‘ilinggous’ (ιλιγγουξ), ‘skotomatikoi’ (σκοτωματιϖν), ‘dinos’ (δινοξ), and ‘skotodinos’ (σκοτοδινοξ). Despite their same subjective meanings for vertigo, the terms have different objective connotations. The term ‘dinos’ connotes either whirling and rotation (as in eddies, whirlpools, or dances) or roundness of goblets or threshing-floors (Liddell & Scott, 1968). The term ‘ilinggous’ also denoted eddies of smoke or whirlpools, but carried the additional sense of mental agitation or losing one's head (Liddell & Scott, 1968). ‘Skotos,’ the root of ‘skotomatikoi,’ carries the connotation of literal and figurative darkness, in the sense of shadows, gloom, or ignorance. Later texts in Latin used the terms ‘scotomia’ (a cognate of the Greek term) and ‘vertigine’ or ‘vertigo’ (from verto or vorto, which denotes either the act of a person turning around or the act of rotating an object).

The Greek terms ‘ilinggous/ilinggon’ and ‘skotodinos’ appear in the works of Plato Ast, 1969, Jowett, 1892 within a context that encompasses inebriation, vertigo, height vertigo, disorientation, and mental confusion (or ‘swimming in the head’). In Gorgias 486a and 527a, ‘ilinggon’ refers to giddiness or ‘swimming in the head’ when faced with final judgement in the afterworld. In Phaedo, the term refers to spinning of the world during inebriation. The same term was used in both Lysis 57 and Protagoras 339e to refer to giddiness, disorientation, and mental confusion during a philosophical discussion or argument. Two other metaphorical uses of the term for a state of intellectual disorientation, though, bear specific reference to situational provocation of vertigo. The term ‘ilinggon’ refers specifically to height vertigo in Theatætus 175d and the term ‘skotodinian ilinggon’ is used in Laws X 892e to compare the sensation provoked by crossing a river of flowing water to the response to a stream of questions. Hence, the terms were used both literally and metaphorically to describe phenomena that we presently term vertigo, space and motion discomfort, and mental confusion.

The contextual use of these distinct Greek and Latin terms in medical texts indicates that they did not denote different forms of dizziness. For example, the anonymous first-century work, De Morbis Acutis et Chroniis (Garofalo & Fuchs, 1997) stated that the ‘skotomatikoi’ and the ‘ilinggous’ were synonymous terms for a condition where “it seems to them that everything is spinning round … and they think they see dark [skotos] instead of light.” The Tardum Passionarum, a fifth-century Latin translation of the first-century Greek text of Soranus of Ephesus, stated bluntly in the section titled ‘Scotomatica’ that “…there is no need to distinguish scotoma from vertigo [vertiginem] and the blurring of vision [that accompanies dizziness], for the latter are, as it were, the parts of which scotoma [scotomatica] is composed.” (Drabkin, 1950) The lack of differentiation between different forms of dizziness was evident in the description of ‘whirling in the heade’ in the sixteenth-century popular work, A Most Excellent Homish Apothecarye (von Braunschweig, 1968):

Many are whom the heade whyrleth so sore/y^t [that] he thinketh the earth turneth upsyde doune [down]/y^e [the] same also hath payne in y^e [the] eye^~ [eyes]/he thinketh y^t [that] a sorte of flyes do flye before his eyen [eyes].

Later sources often viewed “vertigine” (illusory self-motion) and “scotomia” (visual manifestations) as ‘sisters’ [‘sorore’] (Guainerio, 1488) that constituted different grades of vertigo. However, a fourteenth-century text (Gordon, 1498) characterized vertigo as the illusory spinning motion, while scotomia was reserved visual manifestations such as oscillopsia and the illusion of flies (“videat muscas”) before the eyes (folium 28v). The sixteenth-century physician, Domenici Leoni Lunensis (1576) discussed two related disorders, vertigo for the illusory sense of spinning and tenebrosa vertigo for vertigo associated with visual illusions, blurred vision, and lack of visual stability (oscillopsia). Later sources maintained this distinction between simple vertigo (vertigo simplex or morbus vertigo) and complex or tenebrosa vertigo (Physician (Anonymous), 1738)). Although the simple vertigo remained as an illusory sense of spinning, the definition of complex vertigo was elaborated to the extent that it could include phenomena such as diplopia. For example, an anonymous work (Physician (Anonymous), 1738) included the following description of complex vertigo:

Sometimes, as already said, this Affect is accompanied with Dimness and Darkness of the Sight, representing Variety of Colours, and Things to look double and treble, in which Case not only all the other symptoms are existent, but the Circumvolution or Rotation of Things seems to be with a great Violence or Vehemency, insomuch that when the Paroxysm seizes the Patient, he will necessarily fall, unless he catches hold of something to support himself. (pp. 8–9)

As we shall see later, the illusory nature of these sensations led to the classification of all vertigo as hallucinations by Boissier de la Croix de Sauvages (1771) in the late eighteenth century and as an illusion by J. Russell Reynolds (Reynolds, 1855) in the mid-nineteenth century.