Editor—Disturbing symptoms from the use of mobile telephones are being increasingly reported and have been described by Hocking.1 One of us (RAFC) has also collected a series of such cases but has not published them to date.

Many of these cases are characterised by symptoms of dizziness, disorientation, nausea, headache, and transient confusion. Such symptoms might be expected to arise from unilateral stimulation of the vestibular apparatus. This could occur from the direct action of the radiowaves on the endolymph or the hair cells in the semicircular canals or from convection currents set up in the external auditory meatus from the heat of the mobile phone. Most patients complain of a sensation of heating round the ear, often accompanied by reddening of the skin. Blanks et al 2 have shown that there is significant variability in the precise orientation of the semicircular canals, which may result in a predilection to greater thermal stimulation in some people. Because mobile telephones tend to be used in noisy situations, the user holds the instrument much more tightly to the ear than he does a normal phone.

In our opinion there is good theoretical and clinical evidence to support the hypothesis that some people, perhaps 5% to 8% of mobile phone users, have transient symptoms of vestibular disturbance associated with their use. We think that the hypothesis should be tested experimentally as the number of people affected will increase as use of mobile phones increases. It is also important to confirm our hypothesis experimentally to find the mechanism underlying vague symptoms of disorientation and to emphasise that these symptoms do not indicate any greater risk of developing brain cancer, whether or not mobile phones are ultimately shown to have any association with cerebral tumours.

The research required is relatively simple and we would suggest that, in the light of widespread public concern, this work should be included in any programme which is proposed to clarify the issues about safety of mobile telephones.