On examination, a patient's arm resists all attempts at passive movement, gentle or firm, with a marked, apparently motiveless force that does not simply scale with the examiner's own effort, and the same pattern is seen when the examiner tries to reposition his legs and turn his head. Before revealing the answer: is this Gegenhalten?

No, this is more consistent with negativism than with simple Gegenhalten. Gegenhalten is specifically a force-matching resistance to passive movement, typically not obvious with gentle movement, whereas here the resistance is marked and present even with gentle attempts, does not simply track the examiner's own force, and extends across multiple different forms of interference (limbs, head) rather than being confined to passive movement of one limb. This broader, more marked, apparently motiveless resistance to interference generally is what distinguishes negativism, of which Gegenhalten is considered a milder precursor.