A comparison between sniffing and blowing for olfactory testing before and after laryngectomy

Area of Science:

• Otolaryngology
• Neuroscience
• Sensory Science

Background:

• Laryngectomy often leads to olfactory dysfunction due to altered airflow dynamics.
• The precise reason for olfactory loss and the efficacy of different testing methods post-laryngectomy remain unclear.
• Sensorineural olfaction is hypothesized to remain intact, necessitating evaluation beyond standard sniffing tests.

Purpose of the Study:

• To investigate olfactory function in patients after laryngectomy using both odour-sniffing and odour-blowing tests.
• To compare the effectiveness of the T&T olfactometer (sniffing) and Jet Stream Olfactometer (JSO, blowing) in assessing post-laryngectomy olfaction.
• To determine if residual olfaction can be detected and quantified in laryngectomized individuals.

Main Methods:

• Evaluation of 32 laryngectomy patients using T&T and JSO olfactometers, and visual analogue scale (VAS).
• Olfactory testing performed pre-operatively and at 1 month, 6 months, and 1 year post-surgery.
• Comparative analysis of odour threshold results between sniffing and blowing tests.

Main Results:

• Olfactory thresholds significantly worsened across both T&T and JSO tests post-laryngectomy compared to pre-operative levels (p < 0.05).
• The JSO (odour-blowing) demonstrated a significantly smaller increase in olfactory threshold compared to the T&T (odour-sniffing) test (p < 0.05).
• VAS scores also indicated a significant decline in olfactory perception post-surgery.

Conclusions:

• While normal olfaction could not be definitively proven, the odour-blowing test (JSO) proved superior in identifying residual olfactory function in laryngectomized patients.
• Active airflow, as facilitated by the JSO, is crucial for effective odour recognition, surpassing simple scent blowing.
• These findings highlight the importance of airflow dynamics in olfactory perception and suggest tailored testing for post-surgical assessment.