Chapter 4

Specific vocalized complaints in whiplash and minor head injury patients

Mallinson, AI, Longridge NS.

Am J Otol 1998;20(4):809-813.

ABSTRACT

Objective: Subtle complaints of visual-vestibular mismatch may not be elicited in an initial history-taking. Clinicians must be familiar with the nature of these complaints when assessing whiplash patients because other injuries may predominate and patients do not volunteer these more subtle complaints, which may be persisting and sometimes debilitating.

Study Design: A retrospective case review was performed.

Setting: The study was conducted at a tertiary/quaternary referral clinic.

Patients: Patients with whiplash, mild head injury, or both were referred for assessment of symptoms persisting for at least 2 years after their injury.

Interventions: A full history; otolaryngologic examination; including assessment of eye movements, corneal reflexes, and gait; investigation including electronystagmography and computerized dynamic posturography; and history-taking and detailed recording of related complaints were performed immediately before diagnostic workup.

Main Outcome Measures: Many patients had more subtle complaints, which we now recognize as indicative of vestibular pathology, that have not previously been described in detail in the literature and are often generalized using terms such as “dizziness” or “lightheadedness.” It is important to take a detailed history from these patients to delineate their more subtle complaints, because their symptoms frequently do not “fit” into traditional syndromes.

Results: Complaints verbalized by patients were tabulated. On more careful analysis, they can be identified as arising from a mismatch between vestibular information and other sensory information used to maintain balance.

Conclusions: Many patients with the standard vestibular syndromes have the same subtle complaints (apart from the standard vertiginous complaints) that patients with whiplash and minor head injury verbalize. The similarity of the complaints in the two groups indicates that the subtle symptoms are caused by underlying vestibular disease.

KEYWORDS: whiplash, dizziness, imbalance, head injury

Patients with either whiplash injury (correctly called “whiplash-associated disorder” or “WAD”) or mild head injury (also referred to as “mild traumatic brain injury”) often have dizziness. This report, the first of two, delineates complaints voiced by these patients and legitimizes them as being organic. Patients with known organic vestibular disease, such as Ménière’s disease, vestibular neuronitis, or recurrent vestibulopathy voice standard complaints of vestibular dysfunction; however, on direct questioning, they will often report more subtle symptoms, similar to those described by our patients with whiplash. These complaints are described in this paper, and the patients are studied in detail in the second paper. The physical abnormalities in these patients and the consistency of our findings strongly suggest that their complaints have an underlying organic basis.

Although not analyzed separately in this paper, the patients in our second paper were grouped into 2 groups: those with “whiplash only” and those with “mild head injury.” Patients with whiplash without a blow to the head, apart from contact with a headrest, represent a separate group from the patients who also had head injury that met the criteria of mild head injury as originally outlined by Jane (1) and defined precisely by Kay et al. (2). Mild head injury or mild traumatic brain injury is defined as injury with one or more of the following symptoms: loss of consciousness (LOC) for less than 30 minutes, posttraumatic amnesia measured at 24 hours or less, Glasgow Coma Score between 13 and 15 at the 30-minute mark after injury, change in mental state, and neurologic deficits on examination. Mild head injury has also been subcategorized by Jane (1) into 4 grades of severity: grade 0, patients are struck in the head but not stunned (usually seen in athletes); grade 1, people who are momentarily stunned but report no LOC or amnesia; grade 2, concussion results in altered sensation for more than a minute and clouding but no LOC; grade 3, LOC for less than a minute; and grade 4, LOC for more than 1 minute but without coma.

The Quebec Task Force on flexion and extension injury (3) reviewed over 10,000 papers on the subject of whiplash-associated disorder. Many of the papers were classified by the task force as anecdotal case reports and only 294 had scientific data about whiplash. Of these, only 62 were deemed to be scientifically acceptable and clinically relevant. The task force encouraged evidence-based studies on whiplash-associated disorder and called for a collaborative effort in treatment and research.

We have assessed a number of patients who have had dizziness associated with either whiplash or minor head injury. After reviewing the literature (4-10), it was clear that when patients reported traumatic dizziness, this symptom was classified using limited terms, such as “dizziness,” “lightheadedness,” or “imbalance.”

This introductory paper describes the types of complaints that patients with traumatic dizziness report. These complaints have not previously been described in detail, but are characteristic of dysfunction affecting the two reflexes subserved by the vestibular system: the vestibulo-ocular reflex (VOR) and the vestibulospinal reflex.

Complaints of dizziness are usually self-limiting. Pearce (10) found that 70% of patients with whiplash and dizziness had their symptoms settle within 6 months of the injury. The remaining patients with persistent symptoms were likely to have them on a long term basis.

The aim of this paper was to tabulate patients’ complaints after WAD or mild head injury. Although the most common complaints were imbalance and vertigo, some patients reported difficulty identifying motion of self or surroundings. Other patients described feeling as if they are falling or increased susceptibility to motion sickness.

PATIENTS AND METHODS

Patients in this study were referred for assessment of symptoms of dizziness persisting for at least 2 years after a whiplash injury or minor head injury from a motor vehicle accident (“rear ending,” lateral, or head-on accidents). None of the injuries in these patients were worse than a grade 3 mild head injury, defined as LOC for less than a minute.

During assessment, patients had a full history-taking and otolaryngological examination, including assessment of eye movements, corneal reflexes, and gait. They also underwent electronystagmography and Computerized Dynamic Posturography, and a careful vestibular history was taken. Patients were excluded if they had not completed clinical assessment, including electronystagmography and Computerized Dynamic Posturography.

RESULTS

Two patients were excluded because they had not completed clinical assessment. Thirty-six charts were retrospectively analyzed. Specific symptoms reported by the patients were tabulated (Table 1). Table 2 compares the complaints of patients who had only whiplash to those of patients who also had minor head injury. Complaints are very similar between groups; imbalance, nausea and vomiting, and a worsening of symptoms with head movement were reported equally by members of both groups. However, in the group with only whiplash, specific vertiginous complaints were much more common than in the group with whiplash and head injuries.

DISCUSSION

Patients who have dizziness after whiplash, mild head injury, or both frequently do not have acute vertiginous symptoms that specifically indicate any of the traditionally recognized vestibular syndromes. Their complaints are often more nonspecific and, in the literature, have been variously classified as lightheadedness, vertigo, or imbalance without any definition of these terms or any clear understanding of the pathophysiology. Our patients consistently report symptoms that are not ordinarily reported by patients with acute vertigo. Patients will describe subtle feelings of movement of self or surroundings, awareness of imbalance, and physical disorientation. These complaints represent the chronic manifestation of ongoing problems and are legitimate and organic, not anxiety-based or psychogenic, which are often the ascribed causes in patients with vague complaints that cannot clearly be categorized.

What is the relationship between whiplash injury, visual-vestibular mismatch, dizziness, and imbalance? The concept of visual-vestibular mismatch, or “visual vestibular conflict” (11), is particularly important to persons who have reduced tolerance to any such conflict, resulting in motion sickness. The VORs are responsible for producing compensatory eye movements in space. These reflexes are also responsible for the generation of the linear VOR (LVOR), including translational LVORs that act at higher frequencies in response to horizontal eye movements in response to movements of the head on the interaural axis. Vertical LVORs respond to dorsoventral movements, and horizontal and vertical LVORs respond to nasooccipital axis motion of the head (12). This LVOR behaves according to the kinematic requirements of compensatory eye movements during linear motion, and it augments visually driven ocular following information, sometimes referred to as “optic flow” (12).

The etiology of motion sickness is widely believed to be conflicting efforts of the visual and vestibular systems to stabilize images (13). The effects of this mismatch, initially proposed by Reason (14) to result from a neural mismatch, can be devastating in everyday life, as evidenced by patients with extreme motion sickness. It does not result from retinal slip generated by decreased VOR gain (because the blind can also become motion sick); rather, it appears that “motion-sickness provoking” environments may be generated by inadvertent egocentric motor activity (concentrating on a body frame of reference rather than the external world) (15). The symptoms may be provoked as a warning device resulting from an inadequate representation of this ego-spatial relationship in the brain (16).

A similar mismatch or visual-vestibular conflict may also be responsible for mal de debarquement syndrome, or illusion of motion after sailing (“sea legs”) (11). However, why there is such a wide variation in susceptibility to motion sickness or an intolerance for visual-vestibular mismatch among persons is not known. Although there is some evidence that this is correlated with higher VOR gain (17), the only effective medication for treating the symptoms does not seen to affect VOR gain (13). Nevertheless, many people are not affected by visual-vestibular mismatch, although others are unable to read a map or change a radio station in a moving car.

There are many other situations that lead directly to an acute change in vestibular response, and the resulting visual-vestibular mismatch can cause the same symptomatic reaction. These might include cases of vestibular pathology (15). Therefore, sensitive patients could be rendered markedly symptomatic by even minimal vestibular lesions, which is a situation we encounter repeatedly in our clinic. Although some studies have suggested a possible correlation between the level of caloric response and susceptibility to motion sickness (reviewed in 17), experience in our laboratory has not supported this hypothesis.

Neck muscle activations are abnormal or absent in patients with vestibular loss, implying that the vestibulocollic system plays a large role in head stabilization. These neck reflexes can partially compensate for the vestibular system to provide head and trunk stabilization (18). Moreover, sensory information from the neck could substitute for vestibular information in patients with vestibular loss. Stabilization of head position during postural movements relies not exclusively on vestibular and neck reflexes, but on the entire action of the entire postural control system. Therefore, any injury to the neck also has the potential to cause a cervico-vestibular mismatch, and, in particularly sensitive patients, this could be a corollary of motion sickness. The symptoms would include sensations of drunkenness, “sea legs,” or vague unsteadiness. Of note, almost half of our patients with only whiplash also reported true spinning, markedly similar to complaints of patients with classic ear disease. These “traditional” voiced complaints do not necessarily suggest true semicircular canal pathology.

Only one of our patients with head injury reported true spinning; the predominant complaint in this group was unsteadiness, perhaps indicating that the head injury caused a subtle central vestibular (as opposed to peripheral vestibular) lesion. Many physicians are unfamiliar with assessing patients with this type of disease and with recognizing the vague but genuine complaints these patients have. Visual-vestibular mismatch (or cervico-vestibular mismatch) is often difficult to recognize, even after a careful history is taken. In the patient with whiplash, other complaints, which may include acute vertigo or many other possible symptomatic complaints, are often so overwhelming that the minor complaints described in this paper are ignored by the patient unless his or her physician specifically inquires about them.

Table 1. Vocalized complaints in whiplash and minor head injury patients

Table 2. Frequency of patients’ voiced complaints

WAD - whiplash-associated disorder; HI – head injury

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