H – Autism Dictionary

High and Low functioning The terms “high-functioning” and “low-functioning” autism are outdated and inaccurate ways to describe autistic individuals. They are not formal diagnostic categories and can be harmful, leading to misinterpretations of an individual’s needs and abilities. Instead, it’s more accurate and respectful to recognise autism as a spectrum with varying degrees of support needs.
Further reading: https://www.bristolautismsupport.org/functioning-labels-damaging-irrelevant/

Hyper-phantasia is a condition where individuals experience extremely vivid and detailed mental imagery, often described as being as clear and realistic as real-life perception. It’s the opposite of aphantasia, where people lack mental imagery altogether. Those with hyperphantasia can often conjure up detailed mental recreations of all five senses, not just sight.
Further reading: https://neurolaunch.com/hyperphantasia-autism/

Hyperacusis is a hearing condition where everyday sounds seem excessively loud and uncomfortable, sometimes even painful. It’s a form of decreased sound tolerance, where the brain over-sensitizes to auditory input. This can significantly impact daily life, making it difficult to tolerate normal environments and leading to avoidance of social situations.
Further reading: https://www.nhs.uk/conditions/hyperacusis/

Hypervigilance is an increased alertness to the things around us, especially people. This heightened sense of awareness can be triggered by external stimuli such as sounds, flashes and smells. It’s cause is usually PTSD (post traumatic stress disorder).
See Being Perceived
See PTSD