# Ciliary Beat Frequency and Pattern: An Accessible Tool for the Screening of Primary Ciliary Dyskinesia

## TL;DR

This study shows that measuring ciliary beat frequency and pattern can help screen for primary ciliary dyskinesia, a rare genetic disorder affecting cilia function.

## Contribution

The study introduces ciliary beat frequency and pattern analysis as a rapid, accessible first-line screening method for primary ciliary dyskinesia.

## Key findings

- Mean ciliary beat frequency was significantly lower in PCD patients compared to non-PCD patients.
- A CBF cut-off of 5.25 Hz provided high sensitivity and specificity for PCD screening.
- Abnormal ciliary beat pattern helped identify PCD cases with CBF above the threshold.

## Abstract

Background/Objectives: Primary ciliary dyskinesia (PCD) is a rare inherited disorder caused by dysfunction of motile cilia, leading to chronic respiratory disease. Diagnosis is challenging due to heterogeneous and non-specific clinical manifestations and the absence of a single definitive diagnostic test. Current diagnostic strategies rely on a combination of functional, ultrastructural, and genetic analyses. The objective of this study was to evaluate whether ciliary beat frequency (CBF), combined with ciliary beat pattern (CBP) assessment using digital high-speed video microscopy (DHSV), could serve as an effective first-line screening tool to identify patients requiring further diagnostic investigations. Methods: This single-center retrospective study included 65 patients (52 children and 13 adults) with clinical suspicion of PCD. Ciliary beat analysis was performed on nasal or bronchial samples using DHSV and Sisson–Ammons Video Analysis software. CBF and CBP were assessed and compared between patients with confirmed PCD and those in whom PCD was excluded based on transmission electron microscopy (TEM) and/or molecular genetic analysis. Results: Fifteen patients were diagnosed with PCD. Mean CBF was significantly lower in the PCD group compared with the non-PCD group (3.3 Hz vs. 8.1 Hz; p < 0.001). A CBF cut-off value of 5.25 Hz yielded a sensitivity of 78.6% and a specificity of 95.7%. Three patients with PCD had CBF values above this threshold; however, two of them exhibited abnormal CBP. Sample type, patient age, and the presence of airway pathogens did not significantly influence CBF measurements. Conclusions: CBF and CBP analysis using DHSV represents a useful first-line screening tool within a multifaceted diagnostic approach for PCD, allowing rapid identification of patients who should undergo further confirmatory testing.