High score of dizziness-handicap-inventory (DHI) in patients with chronic musculoskeletal pain makes a chronic vestibular disorder probable

Structured symptom questionnaire

A personal interview was performed by the physiotherapist at the respective clinic. The questionnaire consists of 15 items: headache, neck- and/or shoulder pain, TMJ pain, other localized pain, generalized pain, isolated rotatory vertigo, nautical vertigo, dizziness, nausea, fatigue with effort intolerance, visual disturbance, shopping center discomfort, tinnitus, concentration difficulties, short term memory difficulties. Patients answer always, sometimes, or no to each question.

Modified dizziness handicap inventory (DHI)

The Dizziness Handicap Inventory (DHI) is validated for individuals with vestibular dysfunction. The tool consists of 25 items that are scored as always (four points), sometimes (two points), and never (zero point) for a maximum score of 100. A score >60 indicates an increased likelihood of having a fall [9, 11].

The original DHI has a choice of yes, sometimes or no. Since it is easier to respond ‘yes’ than the definitive ‘always’, we have decided to use ‘always’ instead of ‘yes’, re-naming the questionnaire as the Modified DHI. This alternative is used by Elizabeth H Toe [12]. Thus, we expect to get a lower, but probably more accurate DHI-score.

All the questions of the DHI inquiry deal with ‘the condition’, where dizziness is a compulsory part of the symptom complex. The Barany Society characterizes dizziness as a sensation of disturbed spatial orientation [13]. According to the literature a DHI-score >20 is considered abnormal [11, 12, 14].

DHI subscales

According to the reappraisal of the DHI inquiry at the Mayo Clinic of analyzing data from the DHI: calculate a total score and then calculate subscale scores to assess the Physical manifestations, Catastrophic impact, and Emotional impact of dizziness on the patient with benign paroxysmal positional vertigo (BPPV) [10]. Contrary to the original subscales developed empirically by Jacobson and Newman [9], the present subscales are based on an exploratory factor analysis [10].

A confirming answer to question Number 13 ‘Does turning over in bed increase your problem?’ is considered as a strong suggestion of a BPPV [15]. A confirming answer to question Number 25 ‘Does bending over increase your problem?’ supports a suggestion of a BPPV involving the anterior SCC [16].

Table 1 presents the actual questions of the physical-, catastrophic- and emotional subscales. The full DHI questionnaire is shown in the references.

Vertigo

The vertigo appearance in declining frequencies is rotatory-, nautical- and dizziness (18%); isolated dizziness (16%); isolated nautical- (14%); isolated rotatory- (12%); rotatory- and dizziness (12%); nautical- and dizziness (10%); rotatory- and nautical- (4%). This means that 40% of the present patients have a vertigo which does not appear to be rotatory.

Distribution of patients and their percentual DHI scores

The distribution of patients and their percentual total DHI score as well as the DHI subscale scores are given in Figure 1A–D. Forty-one patients (i.e., 84%) out of 49 have a total DHI score above 20. Forty-one out of 49 patients have a physical manifestation DHI subscale score above 20 and 30 out of 49 patients (i.e., 61%) have a physical manifestation DHI subscale score above 40.

Figure 1:

The number of patients on the Y-axis who obtained the percentual score of the (A) total DHI score as well as the DHI subscale scores: (B) physical-; (C) catastrophic-; (D) emotional- shown at the X-axis.

Answers of the physical-, catastrophic- and emotional DHI subscale questions are given in Table 1.

Correlation between DHI scores and number of symptoms

The investigation takes place at five different physiotherapy clinics distributed in urban and rural areas. There is a high correlation between the number of symptoms, typically seen in chronic mc-BPPV [5], [6], [7] and the DHI score among all 49 patients. The greater the number of symptoms, the higher the DHI score was. A similar correlation is observed between the number of symptoms and the physical- and emotional DHI subscale scores.

Subscale scores

Very few patients were found to have scores at the catastrophic subscale. The scores of the emotional subscale are similar to the scores of the physical subscale. However, the emotional questions mostly express sadness of their condition and not a general panic reaction, which the catastrophic subscale indicates. The present subscales are based on an exploratory factor analysis [10] which results in a diagnosis of BPPV. Therefore, we raise the question: Could patients with chronic musculoskeletal pain and a high DHI score have a balance disturbance as the driving force behind the vicious cycle of pain?

Dominant symptom gives the diagnosis

Compound disorders with uncharacteristic symptoms can be interpreted in several ways [7]. If pain is the dominant symptom, less attention is paid to balance related symptoms, and therefore examination of the vestibular system is not included in the general overview. An example of this is the history of a fifty-year-old man who had suffered a road traffic accident. His main complaint was invalidating headache. He visited several different specialists and always opened with ‘the giddiness came first’, but it was always ignored, because the headache was the dominating symptom. We focused on his chronic mc-BPPV and after otolith repositioning according to the diseased SCCs, the headache ceased.

Trauma

Two thirds of the present patients have a history of trauma. Earlier trauma seems to be of relevance in chronic mc-BPPV [1, 4, 19], [20], [21], [22], [23], [24], [25], [26], [27], [28]. The trauma can occur years before the onset of symptoms. This agrees with the statement of Ernst et al. [29] that any trauma of the head, neck, and craniocervical junction can have a major impact on the vestibular system at different sites.

Symptoms

The symptom frequencies of the patients are mostly consistent with previously reported findings of patients with chronic mc-BPPV [5], [6], [7]. The postural control is mainly secured through vestibulo-spinal [30] and vestibulo-reticular reflexes [31]. From a teleological point of view, their purpose is to protect the individual from falling. The lateral vestibulo-spinal reflex is involved in control of torso and extremity muscle tension. The medial one is related to control of the neck. The reticular formation maintains a level of tonus and integrates information from several neural centers. A disturbance in the delicate integration of facilitatory and inhibitory signals in the myotatic spinal reflexes [3] is important for developing musculoskeletal pain.

TMJ-region pain among patients with chronic mc-BPPV is probably due to the involvement of the anterior SCC [7, 16].

In the current study few patients suffered isolated acute attacks of rotatory vertigo. In patients with chronic mc-BPPV any kind of movement illusion can occur [1]. Vertigo has become a part of daily living for many patients with a long history of illness. For example, at shopping centers there is a powerful stimulation of the peripheral view, which stimulates the optokinetic system, which signals directly terminate in the vestibular nuclei complex [8].

Cognitive difficulties could be explained via the vestibulo-thalamic reflex in patients with chronic mc-BPPV [32, 33].

There are indications that the non-classical pathways are abnormally active via a vestibular input in connection with tinnitus [34, 35]. This is not the case for the classical continuing treble or high frequency tinnitus.