Dr. Fabiano de Abreu Agrela Rodrigues, Post-PhD in Neuroscience
Initial Premise: Neurofunctionality vs. Orthopedic Adaptation
Seemingly banal behaviors, such as supporting the head with the hand in a position reminiscent of a dinosaur’s claw, can reveal profoundly different mental and structural architectures. In the clinical setting, labeling without contextualization is a recurring heuristic error. This postural manifestation, when observed in individuals with both Autism Spectrum Disorder (ASD) and Ehlers-Danlos Syndrome (EDS), demands rigorous differential analysis: identical behavior does not imply equivalent functionality.
Autism: Stereotypy as Neurosensory Regulation
In ASD, the “dinosaur hand” tends to be stereotyped, ritualistic, persistent, and resistant to contextual variation. Neurofunctionally, there is involvement of the thalamocortical pathways and dysfunction in the somatosensory cortex, in addition to limbic hyperactivity (particularly of the insula and amygdala), which contributes to atypical sensory patterns. The act of repetitive and precise leaning constitutes an attempt at self-regulation in the face of perceptual instability and environmental overload. It is a marker of internal coherence, not of orthopedic function.
Ehlers-Danlos: Proprioceptive Adaptation to Joint Instability
In EDS, a connective tissue syndrome, such behavior is less ritual and more a biomechanical consequence. Joint hypermobility, chronic pain, and proprioceptive deficit often lead the individual to seek positions of support and relief. Here, the same posture is a somatic adaptive response, dependent on physical discomfort and altered according to the clinical condition. There is no rigidity in the pattern, nor behavioral reinforcement. The supporting hand is a joint necessity, not a sensory code.
Causality and Clinical Semantics: When the Signal Misleads
Confusing the two etiologies can lead to serious diagnostic errors. In ASD, disregarding the symbolic or neurological value of the gesture is to neglect a window of sensory self-regulation. In Ehlers-Danlos syndrome, pathologizing an adaptive gesture as an obsessive ritual is to psychiatize something orthopedic.
This distinction requires more than observation: it requires functional neuroimaging, the study of neurotransmitters (such as striatal dopamine involved in repetition in autism), and postural biomechanical assessment. Human behavior cannot be interpreted without understanding its cause—whether synaptic or collagenous.
Conclusion: Etiology as a Hermeneutic Key
In times of rapid diagnoses and automated protocols, it is urgent to rescue the phenomenological complexity of clinical practice. The “dinosaur hand” is a symbol: of pain or neurodivergence, of adaptation or ritual. To confuse it is to incur diagnostic superficiality. Behavior is a vector, not a point. Meaning, as in any mindreading, depends on the trajectory, not the form.
References
• PINTO, James Yhon Robles; RODRIGUES, Fabiano de Abreu Agrela. Perspectives of the Family System Health Clinic. Cognitiones, v. 6, n. 1, p. 130–144, 2023. DOI: 10.38087/2595.8801.182
• GORIOUNOVA, Natalia A.; MANSVELDER, Huibert D. Genes, Cells, and Brain Areas of Intelligence. Frontiers in Human Neuroscience, v.13, p.44, 2019. DOI: 10.3389/fnhum.2019.00044
