Does Olfactory Training Improve Olfaction in a Population With Normal Sense of Smell?

Summary

Awareness of the sense of smell in the western population has been low. Most people do not think about the consequences of absence of smell (anosmia). Reduction in sense of smell (hyposmia) can influence everyday life. In situations of stress anosmia can be life threatening for example when there is a fire. Cooks may lose their job. Not being able to enjoy food and drink interferes with quality of life. The causes of olfactory dysfunction (OD) vary. Most often OD is associated with upper respiratory tract infections, disease of the nose and sinuses or head injuries. OD may be congenital, age related or associated with neurological disorders. Hyposmia occurs in up to 85% of cases of Parkinson's and may be the first symptom of both Parkinson's and Alzheimer's disease several years before the mental changes occur.

Knowledge and focus on OD has until recently been low among most physicians and treatment options have often not been available. Different approaches to improve OD have been tried with variable effect depending on the cause of OD. There are studies on corticosteroids, zinc gluconate and vitamin A. In recent years, olfactory training has been launched as a promising treatment option. Most studies with olfactory training are done with patients with OD. A recently published review describes 10 studies with olfactory training among 639 patients and concludes that daily stimulation with odorants (odor concentrate) over a limited period time is a promising treatment. The suggested duration of olfactory training varies from 3 to 14 months. Different intensities of olfactory training were compared in patients with post-viral OD. Olfaction was more improved by the high concentration of odorant than by the low concentration.

A small number of studies have shown that the olfactory nerve to some extent can be trained in persons with normal sense of smell, but we need more experience and structured studies to be able to conclude with greater certainty about the effect of olfactory training in this population.

This study examines whether intensive olfactory training improves the sense of smell more than ordinary olfactory training in subjects with normal olfaction (normosmia) and examines self-evaluation of olfactory function.

Conditions

• People With Normal Sense of Smell

Interventions

BEHAVIORAL

intensive olfactory training

BEHAVIORAL

ordinary olfactory training

Sponsors & Collaborators

• Norwegian University of Science and Technology

  collaborator OTHER

• St. Olavs Hospital

  lead OTHER

Principal Investigators

• Ståle Nordgård, md prof · Norwegian University of Science and Technology

• Marit Fagerli, md · St Olavs Hospital, Klinikk for Øre Nese Hals

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2016-12-31

Primary Completion

2019-12-01

Completion

2019-12-01

Countries

• Norway

Study Locations