Involuntary emotional expression disorder in postural tachycardia syndrome

To study the frequency of latent and overt involuntary emotional expression disorder (IEED) in postural tachycardia syndrome (PoTS).

We compared 51 PoTS patients with 15 neurally mediated hypotension (NMH) patients and 12 control subjects using the Center for Neurologic Study-Lability Scale (CNS-LS) for latent IEED and the PHQ-9 questionnaire for depression screening before head-up tilt (HUT). Overt IEED occurrence was observed during HUT.

HUT precipitated overt IEED in 11 (22%) PoTS patients but not in NMH patients or controls. CNS-LS identified latent IEED in 23 (45%) PoTS patients, 5 (33%) NMH patients, and no control subjects. The CNS-LS tearfulness subscale was elevated in PoTS patients compared with controls (P = 0.0006). The PHQ-9 questionnaire scores were elevated in 69% of PoTS patients and 47% of NMH patients. The PHQ-9 score was higher in PoTS (<0.0001) and NMH (P = 0.0002) patients compared with controls.

The study demonstrated frequent occurrence of latent IEED in PoTS and NMH and overt IEED in PoTS without "structural" involvement. HUT was a specific trigger for overt IEED in PoTS. Depression was co-morbid with PoTS. Neurohumoral and cerebral blood flow changes in supine position along with reduced gray matter volume in the insula and cingulate gyrus may underlie susceptibility to IEED. During HUT, cerebral hypoperfusion, rising epinephrine levels, and augmented autonomic arousal provide underpinnings for overt IEED. Clinicians should recognize this entity and counsel PoTS patients and their families. Limiting the duration of orthostatic stress may reduce morbidity.