Abnormal patient, normal test: theotologist’s dilemma

A daily and frustrating occurrence in clinical otology isthe patient with a variety of distressing complaintsdespite normal or non-diagnostic tests. What doesthis mean, and how should we deal with the problem?Medical diagnoses are generally made based on

history and physical examination, followed by theappropriate tests. In addition to blood and urinetesting, we look specifically at structure and function.The patient presents with a number of complaints,and we try to select tests which will confirm our clinicalimpression, rule out other items in the differential diag-nosis, and pick up unexpected findings.In clinical otology, standard tests of function are a

rather meagre handful: audiometric testing, auditorybrainstem response testing (ABR), electrocochleogra-phy and vestibular evaluation. The test–patient discre-pancy has numerous causes and clinical ramifications.Let’s look at just a few.Beginning with the humble tuning fork, consider the

Rinne test. For the 512 Hz fork, the Rinne test turnsnegative (i.e. bone conduction is better than air conduc-tionQ1 ) between 30 and 45 dB conductive hearing loss. Asimple screening test, but definitive? It will miss a25 dB conductive loss. For that, one needs a 256 Hzfork, for which the Rinne test will pick up conductivelosses between 15 and 30 dB. While using sets oftuning forks (from 128 to 1024 Hz) to quantitatehearing loss was common practice in the past, todaythe basic evaluation of a hearing impaired patientrequires audiometry.So, let’s look at the audiogram, the workhorse of

clinical otology. This represents a psychoacoustic dia-logue between patient and audiologist, with many inac-curacies and confounders. It is well known in quantumphysics that even the most passive observer alters aphysical phenomenon, simply by observing it. Howmuch more, then, is this the case in an audiometrictest? Test–retest variability tells only part of this story.In pure-tone testing, consider that we are sampling at

octave frequencies (and using natural octaves, not thetempered octaves of the piano keyboard, which iswhy the beeps sound flat). Even if we think of pitchas progressing just in semitones (and in reality the earcan distinguish several finer gradations in frequency),there are 12 steps from 1 octave to the next. Thismeans that 11 pitches are not tested. Although weoccasionally test fifths rather than octaves (e.g. forQ2

3 kHz), for the most part the pure-tone test is really avery coarse screen of hearing acuity, a ‘Swiss cheese’screen with more holes than substance. A patient maywell have a significant hearing loss that ‘fallsbetween the cracks’ of standard pure tone testing. (Incontrast, the Bekesy test, which assessed all frequen-cies equally, was a much more comprehensive assess-ment of hearing; of course, such testing took longerand was more labour-intensive.) Q3So, the audiogram misses more frequencies than it

catches. But is a slight hearing loss, at say 2354 Hz,really that important, or is it just an irrelevant pieceof data? Setting aside the instinctive answer, which isthat the more we know the more we can understand,consider the patient who complains of tinnitus in theface of a normal standard audiogram, or the patientwith impaired sound discrimination because somespecific frequencies in the consonant range are notheard, even though hearing at 2, 4 and 8 kHz is‘normal’. Does this patient need an ABR, or just amore diagnostic pure-tone test? The cochlea can tellus much more than what we plot as we connect thedots on a standard audiogram.Moving to speech discrimination, the testing para-

digm becomes critically interactive. What is presentedis affected by the audiologist’s voice, by his or hervocal pitch, loudness and accentuation, and also byhis or her finesse, persistence and time constraints.The patient’s level of attention, co-operation and com-prehension are additional variables.The statistics of speech scoring are also deceptive.

An speech recognition test result Q4of 60 per cent doesnot mean that the patient understood 60 out of 100words. The usual short cut here is a list of 25 words,with each correct answer adding 4 per cent, but insome practices this has been pared down to only 20words. Now, if each word represents 5 per cent, is a10 per cent change in discrimination really significant?How about a 15 per cent change? Does the result Q5reallymandate ABR testing or magnetic resonance imaging?While the deficiencies of the audiogram hide ‘in

plain sight’, the limitations of electrocochleographyand ABR testing are generally recognised, and, unlikeaudiography, most clinicians use these latter tests asguides rather than sources of definitive diagnosticdata. Such tests indicate trends rather than provideanswers – trends which become significant if they

The Journal of Laryngology & Otology, 1 of 3. EDITORIAL©JLO (1984) Limited, 2012doi:10.1017/S00222151120024841

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

confirm clinical findings, but which can confound ifnot. This is especially true of electrocochleography,the results of which can vary from audiologist toaudiologist, from day to day and from test to test. Inthis regard, it would be interesting to design a ‘halterelectrocochleogram’ which monitored the electricalresponses of the cochlea over longer periods of time.Interesting normative data relating to barometricpressure, diet and hormonal influences might emerge.What about vestibular testing? Unlike audiometry,

caloric testing is objective. Since Barany’s pioneeringwork, this test has been basically unchanged, andapart from minor ‘tweaks’ in technique (using airinstead of water, for example), the parameters havebeen fixed, the results standardised and reproducible.Surely caloric testing has stood the test of time?But is it a good test? The eminent auditory scientist

Juergen Tonndorf once said that testing vestibular func-tion with calorics is like testing vision with lightningand hearing with thunder. Caloric testing is not physio-logical, but a massively supra-threshold stimulus thatdoes not address the labyrinth in a language it normallyunderstands. The meaning of this is simple but pro-found: a patient may have a clinically significant vestib-ular weakness with a statistically normal caloric test.And, while there are more physiologically appropriatetests of semicircular canal function, such as the rotarychair, the front-line reality remains that caloric testsare easy, cheap, and the standard in clinical practice.So it seems that our otological tests miss many

abnormalities, for several reasons, including: the sizeof the holes in our screening techniques; the appropri-ateness of the set-point for what is considered signifi-cant; and the technical problems inherent in makingtests reliable and consistent. Otological tests are par-ticularly weak at capturing momentary abnormalities.Tests are snapshots, and life is a movie: unless thetest is performed at the moment a transient phenom-enon occurs, the report may well come back as‘normal’. This is particularly a problem in cases of tran-sient dizziness or tinnitus.There is however a deeper, philosophical issue to

consider. What is the definition of ‘significant’? Forotological tests, such a definition is circular. We statethat caloric testing identifies significant vestibularweakness, then define significant vestibular weaknessas one that causes an abnormal caloric response.Instead of being self-referential, these tests need to bepatient-referential. ‘Significant’ needs to be definedas a sign that something is wrong with the patient,not with the test. As the Greeks said, ‘man is themeasure of all things’. The graphs and numbers gener-ated in otological testing serve a function only if theyare measured against the patient’s problems.Physicians live in a visual world, and we are will-

ingly seduced by pictures, numbers, figures andgraphs. Visual data generate an apparently irrefutablepoint of reference for patients, health workers,Q6 healthinsurance companies and lawyers, especially when

such data validate our clinical impression. Visual dataare static and easily shared to build consensus amongtheir interpreters. And so, clinicians are increasinglybecoming testers: record generators rather than clinicalobservers. However, our reliance on (some would sayaddiction to) clinical testing may lead us in a falsedirection that does not benefit our patients. The test isjust a tool, it is not the disease. As the Buddhist injunc-tion warns, ‘do not confuse the finger pointing at themoon, with the moon’. So, while a caloric weaknessof 15 per cent may not in itself be ‘statistically signifi-cant’, when put into the context of a dizzy patient wholateralises to the same side, it becomes ‘the fingerpointing to the moon’.We have now questioned the tests, and it seems that

they have many limitations: they can miss and, worse,mislead. But we still need to deal with that abnormalpatient with normal tests. What to do? Trying to con-vince the patient that ‘your tests are normal andnothing is wrong’ is disingenuous, and just asinadequate as the defensive posture of ‘the patientmust be crazy’.So which is correct, the patient or the test? We need

to accept that actuality trumps theory. As a youngmedical student in Toronto in the 1960s, I recall per-forming cadaver dissection and finding somethingthat was not in the anatomy manual. Confused, Isought out the demonstrator, an old English doctorwith years of experience. ‘Sir’, I said anxiously, point-ing to the structure in question, and then to the book,‘this is not supposed to be here!’. He looked at mecalmly, and uttered words that have continued to res-onate ever since: ‘My boy, never argue with thespecimen’.Patient trumps test. We need to soberly accept the

reality that these tests are rather blunt instrumentswhich may signify but do not conclude. In otology,there are many symptoms and few tests. We haveno way to quantify diplacusis, hyperacusis or painaccompanying inner ear symptoms, to give just afew examples; however, that doesn’t mean thatthese complaints are any less valid, and no amountof ‘normal testing’ will make them disappear.Patients will often convey to us symptoms which donot fit our mental picture of a ‘diagnosis’, andwhich are not confirmed by our tests. We shouldnot discard these complaints simply because theydo not fit. What is, is, and whether or not such symp-toms fit the crude parameters imposed by tests doesnot make them any less real. And making thepatient fit the diagnosis, forcing him or her to liedown on the Procrustean bed of our tests and theories,serves neither patient nor physician. (Greek mythol-ogy tells of the highwayman Procrustes who invitedtravellers to his house and offered them overnightlodgings. Once they accepted, however, he madethem lie down on his iron bed and, being a sticklerfor exactitude, would stretch them on a rack if theywere too short or cut off their legs if they were too

EDITORIAL2

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

long, until they fit the bed exactly. Some of hisvictims died in the adjustment.)Q3So if the patient’s clinical picture and our tests

don’t match, we should not question only thepatient, but the tests too. Clinical tests are not anend, merely a means. They are tools: imperfect,rough, and helpful only if used with a clear under-standing of their limitations, and always with the

clinical picture foremost in our mind. Remember,it’s the patient, not the test.

ANTHONY F JAHN Q1Professor of Clinical Otolaryngology

Columbia University College of Physicians andSurgeons

New York, USA

EDITORIAL 3

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177