![]() Hughlings Jackson proposed the distinction between voluntary vs. The possibility of selective inhibition confirms the dissociation between two vocal generators. 2 Second, volitional inhibitory control can be selectively targeted onto just the former of these pathways without thereby inhibiting the latter. For example, functional neuroanatomic studies in squirrel monkeys and data from clinical populations have demonstrated two distinct pathways of sound production: a limbic cingulo‐periaqueductal circuit involved in the generation of nonverbal utterances, such as groaning, crying, and laughing and a cortico‐basal ganglia‐thalamocortical circuit associated with the production of speech and singing. Thus, our case illustrates two important points regarding the neurocognitive architecture for vocal control, first, dissociation between two pathways for vocalizations. ![]() This indicates that the two different types of vocalizations are associated with distinct neuromotor signals: top‐down control of one type of signal (i.e., involuntary groaning) did not affect the other (i.e., speech). Second, selective inhibition of the involuntary vocalizations did not abolish the ability to speak. This implies that the two different types of vocalizations are generated by two different neural resources that are concurrently active, but the vocal motor apparatus cannot be driven by both generators simultaneously. Importantly, the presence of involuntary groaning interfered with the production of voluntary speech. First, the generation of voluntary speech and groaning behavior did not occur in succession, but in parallel. However, two clinical observations from the case here provide crucial insights into both of these aspects. ![]() Although the association of groaning with neurodegeneration (e.g., PSP) has been established, 1 little attention has been given to its exact phenomenological classification and pathophysiology. In the presented case, constant groaning was the most striking feature and the reason for referral to our clinic. Commencement of 7.5 mg daily dose of aripiprazole also had no effect on the involuntary vocalizations, but led to impulsive behaviors and increased fall frequency. Similarly, discontinuation of quetiapine over several months did not lead to any changes in involuntary groaning behavior. For example, discontinuation of all dopaminergic medication over a period of four weeks led to deterioration of parkinsonism, without changes in groaning frequency or intensity. There was no association of the involuntary groaning behavior with attempted changes in medication. At the time of presentation, the patient was treated daily with 300/75 mg levodopa/carbidopa, 4mg rotigotine, 200 mg amantadine, 75 mg quetiapine, and 20 mg citalopram. Distracting the patient from the effortful inhibitory process led to reemergence of the involuntary sounds. Importantly, although the patient reported that the sound was generated involuntarily, he was able to selectively suppress the involuntary groaning employing, for example, breathing techniques (Video S1, segment B). However, the most striking feature was the groaning behavior. On current examination, the patient presented with parkinsonism, vertical gaze palsy, impaired postural reflexes, and a dysexecutive syndrome, consistent with the diagnosis of PSP‐RS (PSP Rating Scale score 44 Video S1, segment A). The groaning behavior, which was constantly present and only abated during deep sleep, was distressing, particularly for the patient's family. The phenomenological classification and pathophysiological implications of the involuntary groaning behavior are discussed.Ī 66‐year‐old male, who had been diagnosed with PSP four years earlier, presented to our department due to constant groaning, which had insidiously developed over the course of several weeks. Attempts to distract attention from the active inhibitory process led to reemergence of the groaning behavior. 1 Here, we report the case of a 66‐year‐old male with PSP‐Richardson syndrome (PSP‐RS) who presented with constant involuntary groaning that, at times, he could voluntarily suppress. Constant grunting and groaning are involuntary and uncontrollable vocalizations, typical for several types of dementia, and have also been associated with advanced progressive supranuclear palsy (PSP). They range from simple and brief sounds (e.g., throat clearing, lip smacking, or grunting) to complex and socially inappropriate obscenities such as coprolalia. Involuntary vocalizations are a striking feature of several neurological conditions, often associated with movement disorders.
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