Cerebral Disorders
The urge-to-cough (UTC) is a cognitive sensation required to initiate
and inhibit the reflexive cough elicited by stimuli lower than those
normally required to elicit a motor cough. The cough is mediated by the
cerebral cortical or subcortical regions (8). Cough that has no
identifiable medical cause and does not respond to traditional medical
measures used to be called psychogenic, habitual, or tic cough.
Nowadays, the term ”psychogenic” is replaced by ”somatic” cough, and the
term ”habitual” has been replaced by ”tic” cough, according to the
Diagnostic and Statistical Manual of Mental Disorders, 5th (DSM-5)
Edition (9).
The distinction between somatic and non-somatic chronic cough is
occasionally challenging, as patients with chronic cough are more prone
to psychomorbidities such as anxiety and depression, which in turn can
trigger chronic cough. The diagnosis of somatic cough syndrome should
only be made if the patient meets DSM-5 criteria, and not based on the
presence or absence of a nocturnal cough or a cough with a
barking/honking quality. Some categories of patients with somatic cough
disorders (such as children) may benefit from nonpharmacologic trials of
hypnosis or suggestion therapy (10). Tic-cough is a form of vocal or
phonic tics characterized by coughing suddenly, briefly, intermittently,
involuntarily, or semi-voluntarily. It may be associated with other
motor or vocal tics such as throat clearing, sniffing, grunting,
squealing, screaming, barking, blowing, and sucking (11). The diagnosis
of a tic cough is based on the presence of the core clinical elements of
tics such as suppressibility, distractibility, suggestibility,
variability, and the presence of a premonitory sensation, whether the
cough is a single tic or one of many (12). Tourette syndrome is a
neuropsychiatric disorder characterized by the occurrence of involuntary
motor and phonic tics such as coughing, grunting, and wheezing. These
phonic tics can be misdiagnosed as respiratory disorders such as asthma,
upper and lower respiratory tract infections. A careful history and
thorough neurological examination are necessary to make a correct
diagnosis. (13). When chronic cough is associated with cerebral
manifestations such as truncal ataxia, nystagmus, or incoordination, a
central cause should be suspected in the cough center or superior
control area. Primary central causes of chronic cough are extremely
rare. In patients with type-I Chiari malformations, cough may be the
first symptom due to a lesion in the dorsal medullary region of the
brainstem. A space-occupying lesion in the brainstem involving the cough
center or pressing on the efferent fibers may be a rare cause of chronic
cough (14).