Trigeminocervical reflex in fibromyalgia patients

Technical Aspects of Eliciting Trigeminocervical and Trigeminospinal Reflexes in Humans: A Scoping Review

SUMMARY

This scoping review aims to summarize the technical strategies for obtaining trigeminocervical reflex (TCR) and trigeminospinal reflex (TSR) responses. Studies published on TCR or TSR elicitation in humans through electrical stimulation of trigeminal nerve branches were eligible for this scoping review. The data of interest included stimulation parameters, site of stimulation, recording parameters, and the feasibility of TCR and TSR elicitation, in healthy participants. Short-latency TCR responses were regularly obtained in both anterior and posterior neck muscles after electrical stimulation of the supraorbital and infraorbital nerves under voluntary muscle activation. However, without voluntary muscle activation, we found evidence of elicitation of short-latency TCR components only in the posterior neck muscles after supraorbital or infraorbital nerve stimulation. Long-latency TCR responses were regularly obtained in the anterior and posterior neck muscles in studies that evaluated this technique, regardless of the trigeminal branch stimulation or muscle activation status. Short-latency TSR components were not obtained in the included studies, whereas long-latency TSR responses were regularly recorded in proximal upper limb muscles. This scoping review revealed key heterogeneity in the techniques used for TCR and TSR elicitation. By summarizing all the methodological procedures used for TCR and TSR elicitation, this scoping review can guide researchers in defining optimized technical approaches for different research and clinical scenarios.

Late component of trigemino-cervical reflex: changes according to age and gender

BACKGROUND

Trigemino-cervical reflex (TCR) is a protective reflex which is elicited by the stimulation of any branch of the trigeminal nerve. After infraorbital stimulation, an early and late components have been described. The aim of this study was to find out whether there are age- or gender-related changes in the long-latency (RII) component of TCR.

METHOD

We included consecutive 53 healthy subjects (20 men, 37.7%) who had normal neurological examination. The mean age was 45.1 ± 14.3 years (age range 18-75 years). TCR was recorded simultaneously from bilateral sternocleidomastoid (SCM) and splenius capitis (SC) muscles with surface electrodes after stimulating right or left infraorbital branch of the trigeminal nerve, separately. We compared latency, amplitude, and duration according to gender and age.

RESULTS

The amplitudes of SC responses were significantly higher in women compared to men. The duration of SCM response was significantly longer in subjects above the age of 50 years compared to younger patients. The latency of the SC response was significantly delayed above the age of 40 years.

CONCLUSION

There are age- and gender-related changes in TCRs probably due to changes in the motoneurons of the SC and SCM muscles.