Abstract
Objective Review pre-requisites of valid consent.
According to NSW Health Guidelines, consent, to be valid, entails four attributes: it be freely given; the patient must have capacity; it must be ‘informed’; it be specified to a particular act or therapy. There are two unvoiced assumptions that underpin these requirements: that the mind is relatively ‘fixed’ over time and that awareness can be reliably measured.
Parietal lobe lesions, in previously normal adults, can cause cognitive deficits of: agnosias – neglect syndromes of illness; body image of self and others; higher order sensations, graphesthesia; motor imagery, self-reflection episodic memory retrieval, praxis, empathy, emotional content of speech. Degree and timing of recovery of each lost function, if it occurs, varies.
An ill person may freely withhold consent, though the converse does necessarily hold: the giving of consent does not mean a valid choice was made – if awareness was impaired. Capacity, and ‘informed’ consent, especially in parietal lesions, for fully understanding implications of a possible future outcome – which, in the main, is what matters – is very difficult to establish with current neuropsychological tools. This leaves only the specificity of consent possible. Later recovery from the lesion, may allow for valid consent.
Conclusion Medico-legally, these provocative challenges will only increase in the future with an ageing population and more stroke survivors. The questions are not merely hypothetical: difficulties also arise in the spectrum of minimal cognitive impairment to dementia, where the burden of disease may fall on different cerebral lobes.
