Læknablaðið : fylgirit - 01.06.2005, Page 12

ABSTRACTS / XXIX CONGRESS OF THE NORDIC ASSOCIATION OF OTOLARYNGOLOGY
S-lll BALANCE
Abstract no.: 004
Nils Gunnar Henriksson: In Memoriam
Máns Magnusson, Lund University Hospital, Sweden
Nils Gunnar Henriksson was born on the 7th of January 1920 and
grew up in the town of Sundsvall. As a young medical Doctor at
the department of Otorhinolaryngology in Lund, he was given
the problem of recording and defining slow phase velocity eye
movements in nystagmus. At the time electrical registration of
eye movements was just described. NG Henriksson applied a
simple derivation function to the recordings, which returned the
slow phase velocity. This could be performed automatically dur-
ing the recordings by filtering the electrical signal. He presented
the results in his thesis in 1956 with Jongkees as examinator.
Electronystagmography was spread over the world and Nils
Henriksson went to Cesar Fernandez lab in Chicago for a post-
doc period. There he observed that repeated caloric irrigation
in cat reduced the responses. This was later use in describing the
vestibular adaptation by Fernandez group.
Back in Lund Henriksson set up a vestibular lab. Were he
engaged in different research projects. He investigated the elastic-
ity of the membranous labyrinth, recorded lateropulsion during
caloric irrigation and did the first recordings of postural control
with force plates called the ‘Electric Romberg test’. Later, and
together with llmari Pyykkö recordings of voluntary eye move-
ments were introduced as a clinical tool in Scandinavia.
Nils Gunnar Henriksson was a warm personality with a genu-
ine interest in education both of students and colleagues. At least
two generations of Scandinavian otolaryngologists heard him lec-
ture and were inspired. In fact N G Henriksson always inspired his
surrounding, and his impact on international research and clinical
applications in otoneurology remains.
Abstract no.: 005
Update on Clinical Vestibular Physiology
Lloyd B. Minor, M.D. Andelot Professor and Chairman. Department of
Otolaryngology-Head and Neck Surgery. The Johns Hopkins University
School of Medicine
Advances in the diagnosis and treatment of vestibular disorders
continue build at a rapid rate. Our understanding of the physi-
ological processes that underlie vestibular function and of the
consequences that disorders of the labyrinth can have on of these
processes has led to many of these advances. This talk will focus
on two vestibular disorders for which recent research has led to
improvements in diagnosis and treatment.
Dehiscence of bone overlying the superior semicircular canal
can result in sound- and/or pressure-induced vertigo and oscil-
lopsia. The signs and symptoms of this disorder can be explained
based upon the bone dehiscence of the superior canal creating a
third mobile window into the inner ear. Patients with this disorder
can also have an air-bone gap on audiometry in the absence of any
middle ear pathology. The threshold for eliciting a response for
a vestibular evoked myogenic potential is characteristically lower
than normal in patients with superior canal dehiscence (SCD)
syndrome. Surgical repair of the dehiscence with a plugging pro-
cedure can be beneficial for patients who are debilitated by the
symptoms of SCD syndrome.
Meniere’s disease remains a common cause of episodic vertigo
and fluctuating sensorineural hearing loss. Intratympanic injec-
tion of gentamicin has been used to successfully control vertigo
in patients for whom this symptom has been refractory to medical
management. Recent studies have increased our understanding
of the effects of gentamicin on vestibular function in the treated
ear. Analyses of the three-dimensional angular VOR evoked
by rapid head movements (head thrusts) indicate that vestibular
function is reduced by the gentamicin treatment and that the level
of reduction of the VOR is predictive of control of vertigo. This
reduction in the VOR after gentamicin treatment is not as great as
that seen after surgical ablation of vestibular function.
The clinical management of vestibular disorders remains a
challenge. Basic and clinical research into vestibular processes
holds strong promise for continued advances that benefit our
patients.
S-IV CONTROVERSIES IN REFLUX
Abstract no.: 006
Too much acid orfaulty defence?
Holbrook WP1, Guðmundsson KG2, Theodórs Á2
■University of Iceland, 2University Hospital, Reykjavík, Iceland
Tooth erosion is the loss of tooth substance caused by acid that
may be: a) gastric, as a result of reflux (intrinsic erosion); b)
dietary (extrinsic), usually caused by acidic drinks; or c) envi-
ronmental. Saliva offers the only defence against tooth erosion
through the diluting effect of salivary flow or the neutralising
effect of salivary buffers. Objectives: A standardised procedure
was developed for examining patients with dental erosion.
Subsequently, 249 patients were examined with the aim of deter-
mining the relationship of risk factors and protective to erosion.
Methods: Erosion was scored separately for anterior and poste-
rior teeth by one clinician and was graded as severe if it extended
into dentine and mild if it was confined to enamel. Data were
collected on: consumption of acidic drinks, salivary flow rate, pH,
and buffer capacity. Gastro-intestinal investigations included 24-
h monitoring of oesophageal pH, oesophageal manometry and
gastroscopy. The presence of pathological reflux, hiatus hernia
and Helicobacter sp was determined. Results: Severe molar ero-
sion (24 subjects) was significantly associated with at least one of
the parameters indicating gastro-oesophageal reflux disease (OR
1.58; p<0.001). Erosion of anterior teeth (severe =72 subjects)
was also significantly associated with reflux (OR 1.33; p<0.005).
Consumption of >0.5L acidic drink per day indicated a dietary
risk for erosion. No association of dietary risk factors and molar
erosion was seen but the association was significant for incisor
erosion (OR 3.17; p<0.001), especially when severe. Salivary
parameters were less clearly associated with erosion except for a
low salivary buffer capacity that was associated with severe ero-
sion of the anterior teeth (chi-square=6.57; p<0.05). Conclusions:
12 Læknablaðið/Fylgirit 51 2005/91