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Updated: Dec 25, 2025
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Published on: March 4, 2014
Reliability of phrenic nerve conduction study: In healthy controls and in patients with primary lateral sclerosis
Maria Claudia Torrieri1, Bruno Miranda2, Marta Gromicho3
1Centro Regionale Esperto per la SLA, Department of Neurosciences "Rita Levi Montalcini", University of Turin, Italy.
Objective:
Phrenic nerve conduction study is a marker of hypoventilation in amyotrophic lateral sclerosis. We aimed to evaluate its intra-rater reliability in healthy subjects and in a cohort of Primary Lateral Sclerosis (PLS) patients.
Methods:
Eighteen healthy subjects and 16 PLS patients were included. All subjects underwent three phrenic nerve conduction evaluations (time interval: 1 week for healthy controls; 1 year for PLS patients). We analyzed intra-rater reliability for five parameters of the diaphragmatic motor response: latency; negative-peak duration, area and amplitude; peak-to-peak amplitude.
Results:
Healthy subjects showed excellent inter-test reliability for most parameters (coefficients of variation <10%). In PLS patients coefficients of variation resulted <10% for latency and peak-to-peak amplitude, <20% for remaining parameters. Inter-test reliability was excellent for latency and peak-to-peak amplitude [intra-class correlation coefficient (ICC) > 0.9] and good for negative-peak amplitude and area (ICC 0.75 ≥ 0.9); duration was not reliable (ICC = 0.383). Negative peak and peak-to-peak amplitude had the least random error (respectively ±0.136 mV and ± 0.177 mV). All parameters showed homoscedasticity (R2 < 0.1).
Conclusions:
Intra-rater reliability is high for phrenic nerve study, especially for latency, peak-to-peak and negative-peak amplitude.
Significance:
Phrenic nerve conduction study is a reliable method to monitor respiratory function.
