J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.37.7.802 on 1 July 1974. Downloaded from Journal ofNeurology, Neurosurgery, and Psychiatry, 1974, 37, 802-810 Abnormalities of taste and smell after head trauma PAUL J. SCHECHTER AND ROBERT I. HENKIN' From the Section on Neuroendocrinology, National Heart and Lung Institute, - National Institutes of Health, Bethesda, Maryland 20014, U.S.A. SYNOPSIS Abnormalities of taste and smell were studied in 29 patients after head trauma. These abnormalities included decreased taste acuity (hypogeusia), a distortion of taste acuity (dysgeusia), decreased smell acuity (hyposmia), and a distortion of smell acuity (dysosmia). This syndrome can occur even after minimal head trauma and can begin months after the moment of injury. The patients exhibited a significant decrease in total serum zinc concentration (patients, 77 + 3 Vg/100 ml, mean + 1 SEM, vs controls, 99 + 2 jg/100 ml, P> 0-001) and a significant increase in total serum copper concentrations (113 + 4 Cug/100 ml vs 100 + 2 [ug/100 ml, P <0-001) compared with control subjects. Symptoms of hypogeusia, dysgeusia, and dysosmia are frequent sequelae of head injury and are important to the patients and to their care after trauma. Protected by copyright. Loss of olfactory acuity after trauma to the head disturbances (Mifka, 1965). Usually decreased is a well-recognized phenomenon and has been taste acuity has been reported to be accom- estimated to occur in 1.3% to 65% of all head panied by decreased olfactory acuity. In the injuries (Laemmle, 1931; Sumner, 1964). Blows majority of cases return of taste acuity has been to the occiput have been reported as more likely reported in the course of time, suggesting that to produce loss ofsmell, presumably by a contre- this abnormality is more amenable to correction coup effect, than blows to the forehead or other than post-traumatic smell loss (Sumner, 1967). sites on the head (Sumner, 1964) and even trivial No relationship between severity of head injury injuries have been shown to result in olfactory and the occurrence or duration of taste loss has sensory deficits (Sumner, 1964). In addition, been previously reported (Sumner, 1967). distortion of odours has been described after Distorted taste sensations have been reported head trauma (Leigh, 1943; Sumner, 1964, 1967). to accompany post-traumatic taste loss (Sumner, Spontaneous recovery of olfactory acuity has 1967). The incidence of distortion of either taste http://jnnp.bmj.com/ been claimed in 8% to 3900 of patients suffering or smell or both in patients with post-traumatic from post-traumatic loss of smell (Leigh, 1943; taste loss has been estimated to be between 6% Sumner, 1964). and 33%o (Leigh, 1943; Sumner, 1964, 1967). On the other hand, abnormalities of taste However, the presumed diagnosis of 'anos- sensation after head injury have received much mia' or 'ageusia' has been made in these studies less attention and have been reported to occur on the basis ofclinical subjective reports, without less frequently than do olfactory disorders. The quantitative measurements to specify the degree first description of taste loss after head trauma or extent of the taste or smell losses. on September 23, 2021 by guest. was made by Ogle in 1870. Since that time, addi- In this paper we present data on 29 patients tional cases of post-traumatic taste loss have who experienced abnormalities of taste and been described in the literature. The incidence of smell after head trauma. Quantitative estimates this condition has been estimated to be approxi- of the losses of taste and smell were made. The mately 0-40/o of all head injuries, a much lower relationship ofthe sensory losses to alterations in incidence than that for post-traumatic olfactory trace metal metabolism will be discussed. I Address for correspondence: Dr Robert I. Henkin, Section on Neuroendocrinology, Experimental Therapeutics Branch, National METHODS Heart and Lung Institute, Bldg 10, Room 7N262, Bethesda, Maryland 20014, U.S.A. On the bases of careful evaluation of symptoms of 802 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.37.7.802 on 1 July 1974. Downloaded from Taste and smell changes after head trauma 803 approximately 400 patients with taste and smell com- Phantosmia Intermittent or persistent odour, plaints we have described alterations in taste and pleasant or unpleasant, perceived when no apparent smell perception as follows (Henkin, 1971): odorant is present. ABNORMALITIES OF TASTE Hypogeusia Decreased to taste sweet, sour bitter tastants. Heterosmia Inappropriate smell of consistent ability salt, and/or nature associated with odorants. This smell is Ageusia Inability to detect or recognize any tastant unusual and unexpected but not necessarily foul or (operationally defined as inability to detect or recog- obnoxious. nize saturated solutions of NaCl or sucrose, 500 mM HCI, or 8 M urea). MEASUREMENT OF TASTE AND SMELL ACUITY Taste acuity was measured by determining detection and Dysgeusia General description of any distortion of recognition thresholds for representatives of the salt, normal taste perception. sweet, sour, and bitter taste qualities by a forced- choice, three-stimulus drop technique (Henkin et al., Cacogeusia Abhorrent, obnoxious taste produced 1963; Henkin et al., 1971). Sodium chloride was used by oral introduction or mastication of food or as representative of the salt taste quality; sucrose, for drink. Foods most commonly eliciting this symptom sweet; HCl, for sour; and urea, for bitter. 'Detection are eggs, meats, poultry, fish, garlic, onions, threshold' was defined as the lowest concentration of tomatoes, coffee, chocolate, and most foods fried in solute consistently detected as different from water. oil or fat. 'Recognition threshold' was defined as the lowest concentration of solute consistently recognized correctly as salty, sweet, sour, or bitter. Taste thresh- Phantogeusia Intermittent or persistent taste per- Protected by copyright. ceived in the oral cavity independent of external olds were measured on one to four separate occa- stimuli. This taste may be salty, sweet, sour, bitter, sions in each subject. The lowest detection and metallic, or indescribably obnoxious. recognition thresholds were used for analysis when- ever more than one measurement was obtained. Heterogeusia Inappropriate consistent taste quality Olfactory acuity was measured by determining produced by oral introduction or mastication of food detection and recognition thresholds for the vapours or drink. This quality is unusual and unexpected but of pyridine in water and for nitrobenzene and thio- not necessarily obnoxious-for example, all food phene in mineral oil by a forced-choice, three- tastes salty or sweet. stimulus sniff technique (Henkin et al., 1971; Marshall and Henkin, 1971). Smell thresholds were ABNORMALITIES OF SMELL Hyposmia General de- measured on one to three separate occasions. The crease in olfactory acuity. lowest threshold was used for analysis whenever more than one measurement was obtained. Anosmia Inability to detect or recognize any vapour at primary or accessory areas of olfaction MEASUREMENTS OF METAL METABOLISM Serum con- (Henkin, 1967b). centrations of zinc and copper and 24 hour urinary http://jnnp.bmj.com/ excretion of these metals were determined. Blood and Type I hyposmia Inability to detect or recognize urine samples were collected in metal-free tubes and any vapour at primary area of olfaction but main- plastic containers, respectively, as previously de- tenance of acuity at accessory areas of olfaction scribed (Meret and Henkin, 1971). Measurements of (Henkin, 1967b). zinc and copper were carried out by atomic absorp- tion spectrophotometry on an IL Model 153 atomic Type II hyposmia Decreased acuity at primary area absorption spectrometer by a method described of olfaction with maintenance of acuity at accessory previously (Meret and Henkin, 1971). on September 23, 2021 by guest. areas of olfaction (Henkin, 1967b). SUBJECTS The experimental subjects were 29 Dysosmia General description of any distortion of patients, 17 males and 12 females, mean age 49 normal smell perception. years (range: 22 to 76 years), 28 Caucasians and one Negro (Table 1). These patients were referred to the Cacosmia Abhorrent, obnoxious smell produced Taste and Smell Clinic at the Clinical Center of the by the inhalation of odorants. Odorants which National Institutes of Health by their personal most commonly elicit this symptom are from per- physicians for evaluation of subjective complaints fumes, soaps, automobile exhaust, hair sprays, and referable to taste and/or smell abnormalities. The from most foods which elicit cacogeusia. mean duration of symptoms at the time these J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.37.7.802 on 1 July 1974. Downloaded from 804 Paul J. Schechter and Robert L Henkin t3 O H [+1+1+1+1+l1+ +1 +1+1+! I + + q Q' 0i ++ ++++++I*++++++ ++ + ++++++++ +1 I! 02In II I+++I I+I+++I + +1 +1+1+11+ + m :s IA bo ++ ++II+I+I++III+ I+ + ++I+I+++ t- 4-0 6. 110 0 C40 6L ..-;;E E. E -;. m=e 40 Protected by copyright. m0o mo X voooo o t!o om - 4t 0 0 szCq -.+ I +e..++±N+ ++ ++ ++ + +++ +++ + 4'. 1. 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