Be as specific as possible in documenting the level of alertness, making note of what the patient can or cannot do in response to which stimuli (see the section "The Neurologic Exam in the Comatose or Uncooperative Patient" in Neuroanatomy Through Clinical Cases, Chapter 3). We can test attention by seeing if the patient can remain focused on a simple task, such as spelling a short word forward and backward (W-O-R-L-D / D-L-R-O-W is a standard), repeating a string of integers forward and backward (digit span), or naming the months forward and then backward. Normal digit span is 6 or more forward, and 4 or more backward, depending slightly on age and education. It normally takes up to twice as long to recite months backward as forward. Note that these tests of attention depend on language, memory, and some logic functions as well. Degree of cooperation should be noted, especially if it is abnormal, since this will influence many aspects of the exam.
Level of consciousness is severely impaired in damage to the brainstem reticular formation, and in bilateral lesions of the thalami or cerebral hemispheres (see Neuroanatomy through Clinical Cases Figure 2.23). It may also be mildly impaired in unilateral cortical or thalamic lesions. Toxic or metabolic factors are also common causes of impaired consciousness because of their effects on the structures mentioned here. Generalized impaired attention and cooperation are relatively nonspecific abnormalities that can occur in many different focal brain lesions, in diffuse abnormalities such as dementia or encephalitis, and in behavioral or mood disorders.