The Effects of State Anxiety on Hoffman (H) Reflex Parameters in Female University Students

Anxiety, as one of the most common and costly problems in Iran and all over the world, comprises both physical and mental disorders. Previous research has proposed that spinal reflex modulation may mediate anxiety-related changes in postural control. This study aimed to investigate if the H-reflex parameters are influenced by state anxiety.

A group of 20 healthy female university students with a low anxiety score (lower than 42, based upon the Schpilberger’s questionnaire) were recruited in this study and the H-reflex of their Soleus muscle was recorded in four positions. The tested positions included the standard prone lying (the reference position), standing on level ground; and two stability threatening positions including standing on the center and at the edge of a one-meter height stool. The outcome measures were the latency, amplitude and the amplitude needed to record the reflex.

No significant differences were shown in the latency of the H-reflex among the four tested positions (p>0.05). In terms of the amplitude of the reflex, however, significant differences were found between all positions when compared to the reference position (prone lying) (p=0.001). There are significant differences among all four positions in amplitude needed to record the H-reflex (p=0.034), while the Bonferoni test revealed the significant difference only between the position of standing at the edge of the height relative to the standard prone lying position (p=0.041).

The results of this study showed that any postural perturbation results in brain activities and affects more on the amplitudes rather than the latency of the H-reflex. These findings may be helpful in a better understanding of the standing balance in healthy people and people suffering from postural instabilities, fear of falling, elderly persons and also hemiplegic patients.