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Advanced Neurology POTS with tics versus tic-like behaviors

changes in her life circumstances. She initially developed in the autonomic nervous system have been proposed as
frequent inhaling spasms, which were followed by a potential pathophysiological explanation for functional
jerking movements affecting her face, neck, and limbs, neurological symptoms. 49
including self-hitting, dropping objects, and occasional Despite extensive research, the exact pathophysiology
situation-specific rude gestures. Over the following of POTS remains elusive and treatment interventions
months, she developed six prolonged episodes of bilateral need to be tailored to the individual patient. 50,51
rigidity with unresponsiveness and preserved awareness, Working hypotheses have mainly focused on baroreflex
prolonged episodes of fixed dystonia, intermittent leg abnormalities and largely overlooked the possible role of
weakness, fatigue, and joint pain. In addition to her cortical centers controlling the autonomic nervous system,
diagnosis of POTS, she had a longstanding history of despite their frequent involvement in autonomically
neurodevelopmental disorders (high-functioning ASD mediated paroxysmal disorders. In a recent study on the
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and developmental coordination disorder). She did not role of fear conditioning in POTS, Norcliffe-Kaufmann
report neurodevelopmental motor or vocal tics. She et al. showed that patients with POTS respond to
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received input from the psychotherapy services for her
disabling functional neurological symptoms, which had verticalization with increased heart rate, catecholaminergic
caused her to quit her job in retail. She also required secretion, hyperventilation and lower speed in middle
support with self-care and food preparation. There was cerebral arterial flow compared to controls. Crucially, they
no collateral history of childhood tics or family history also showed that tachycardia can be induced by the mere
of tics. At the time of her specialist assessment, she was announcement of imminent verticalization rather than the
positional change itself, indicative of fear conditioning.
using a wheelchair. Throughout the consultation, there Based on their findings, the authors concluded that patients
was evidence of intermittent and distractible jerking
movements mainly affecting her neck and limbs, as well as with POTS suffer from a “fear-conditioning behavioral
complex vocalizations. response” to the thought of standing, and that POTS could
be conceptualized as a “functional psychogenic disorder.” 53
4. Discussion The notion that fear conditioning alone is sufficient to
To the best of our knowledge, this is the first study assessing explain POTS has been questioned by other authors. 54-57 It
the prevalence and clinical correlates of POTS in patients has been pointed out that patients with POTS have shown
diagnosed with neurodevelopmental tic disorders (GTS) signs of altered physiological parameters, including lower
or functional tic-like behaviors. In our clinical sample, blood volume and lower stroke volume, especially when
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the prevalence of POTS was 0/638 in the GTS group and upright, compared to healthy participants. The increased
4/177 (2.3%) in the functional tics group. The four patients rate of entry of norepinephrine into the venous drainage
with POTS and functional tics were young females, with age of the heart while patients with POTS are supine, might
at assessment ranging from 17 to 24 years. They all fulfilled be caused by multiple mechanisms beyond conditioned
the diagnostic criteria for functional tic-like behaviors fear of orthostasis. Treatment interventions that counter
proposed by the ESSTS and half of them presented with orthostasis-induced decreased venous return to the
other functional neurological manifestations (non- heart have been shown to be at least partly effective in
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epileptic attacks, functional weakness, and functional decreasing orthostatic tachycardia. In general, POTS is
dystonia). a syndromic condition presenting with a range of multi-
system abnormalities – small fiber neuropathy, slow gastric
The possibility of shared mechanisms and symptoms
between POTS or other autonomic disorders and emptying, autoimmune markers, among others – that are
at best distantly related to excessive orthostatic tachycardia.
functional neurological disorders has been the subject Moreover, it has been shown that POTS can develop among
of research and recent scientific debates. Specifically, it 54
has been reported that there is often a clinical overlap the sequelae of systemic infections, including COVID-19.
in functional neurological symptoms such as fatigue, When addressing the pathophysiology of POTS,
dizziness, and non-specific pain, which are often reported it is important to distinguish between correlation and
by patients with POTS. 46,47 These clinical overlaps suggest causation. Patients with POTS commonly report anxiety
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the possibility of shared underlying mechanisms, as the and affective symptoms, but the mechanisms linking
autonomic nervous system imbalance associated with autonomic dysfunction and psychiatric symptoms is
POTS presents with excessive tachycardia and symptoms of not well understood. 46,48 As with other chronic illnesses,
cerebral hypoperfusion in the upright position. Although patients with POTS are more likely than healthy controls
48
the exact relationship between autonomic dysfunction to report anxiety and to score higher on questionnaires
and functional disorders remains unclear, abnormalities assessing awareness of physical sensations. While
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Volume 4 Issue 2 (2025) 106 doi: 10.36922/an.8525