L. B. W. Jongkees

Directional Hearing Capacity in Hearing Disorders

Jongkees & Groen investigated from which direction a test person with closed eyes would estimate that a sound is coming. In order to obtain objective and measurable results they used a graduated circle (radius 50 cm) along which the sound source could be moved and on which the test person was requested to indicate where he thought the source was situated. As a diagram of his directional hearing, the subjective place, as indicated by the test person, was plotted as a function of the objective place, both in degrees as marked on the arc graduation.Directional hearing is examined in a group of patients suffering from various types of loss of hearing. The results are compared with the diagram for directional hearing in the horizontal plane as found in a series of normal test subjects. Statistically a probable limit value for directional hearing in the horizontal plane is obtained by using Wilcoxons symmetry test.Otitis media chronica, atresia, nerve deafness, otosclerosis, fenestration, tympanoplasty and uni...

On the Effect of Continuous Acceleration

In a series of experiments van Egmond, Groen & Jongkees have given a mechanical analysis of the phenomena in response to the stimulation of the semicircular canals. They stated that the system of the endolymph-cupula is a pendulum system, sensitive to angular acceleration and following the mechanical laws.

Treatment of Bell's Palsy

FOR MANY ‘YEARS surgical treatment of facial paralysis has given us the opportunity to inspect the diseased facial nerve. The work of Ballance and Duel,’ Bunnell,2-‘ and many others has made us familiar with the aspect of the nerve traumatized by an injury of the head, damaged by the instruments of an ear surgeon, eaten by an otitis, or destroyed by a tumor. The diagnosis of facial palsy due to these causes is not very difficult and the opinion about their origin does not lead to great controversy. But there is another group, and an important one too, where the cause is not ap arent at all; the paralysis which does not P ollow an operation or a trauma of the head, where no tumor and no otitis can be found, where no herpetic eruptions are present, and which does not seem to be the sequela of poliomyelitis; the palsy which begins abruptly without any apparent cause, often, but not always, accompanied by pains deep in the ear, the facial aralysis 21 frigore, rheumatic palsy, Bell’s pa P sy. It is not the disease described in 1829 by Sir Charles Bell,6 who gave a perfect description of the motor function of the facial nerve but did not describe the disease that now bears his name. The diagnosis of Bell’s palsy is a diagnosis by elimination and there is hard1 any unanimity, either about its origin or a i: out its treatment. More unanimity is possible, however, as the histopathology of Bell’s palsy is better known and as the results of conservative and surgical treatment can be better predicted. Inspection of the diseased nerve in early cases of Bell’s pals has taught us that the pathology of this isease can always, or at least in the greatest ma’ority of cases, be found

On the Action of Linear Accelerations upon the Otoliths

SUMMARYIn 10 rabbits, examined within 48 hours after unilateral labyrinthectomy, we found three with a direction-fixed positional nystagmus to the intact labyrinth and seven with a direction-changing positional nystagmus. All the rabbits with direction-changing positional nystagmus showed in one or more positions a nystagmus of both eyes in opposite directions (i.e. in the left eye a nystagmus to the left and in the right eye one to the right).All 10 rabbits showed in the lateral positions a stronger nystagmus when they were lying on the operated side than when they were lying on the side of the normal ear.In these rabbits the nystagmus was also stronger in the prone position than in the supine position.In nine rabbits we studied the Bechterew nystagmus. No influence of the above-mentioned positions was found upon this nystagmus. This makes it highly probable that the changing of the size of the positional nystagmus in different positions after unilateral labyrinthectomy has to be sought in the action of ...

Further Investigations into a Peculiarity of Normal Directional Hearing

When plotting the subjective location of a sound against the objective one on an ordinate graph system an S-shaped curve appears. Some factors which might influence or explain the S-form were examined. From the results of these tests no explanation for the origin of the S-curve could be made.

On Nystagmus Provoked by Central Stimulation: Preliminary note

The effect of various vestibular influences (alcohol, rotation, calorisation, optokinetic stimulation, necktorsion and parallel swing) on nystagmus, provoked by electric stimulation of the nystagmogenic centre of Bergmann, Lachmann and Monnier is discussed. In some cases pure addition or subtraction of effects results (rotation) in others centrally provoked nystagmus is depressed (alcohol) or increased (optokinetic). Cinnarizine does not influence the nystagmus provoked by central stimulation.