Cognitive symptoms usually improve over two to four weeks, and they commonly outlast the headache, which is why people feel physically recovered but mentally slow. Where brain fog persists beyond that, sleep and mood are more often responsible than the original injury.
Cognitive symptoms usually improve over two to four weeks, and they commonly outlast the headache, which is why people feel physically recovered but mentally slow. Where brain fog persists beyond that, sleep and mood are more often responsible than the original injury.
It is worth breaking the phrase down, because the parts respond differently. What people describe is usually some combination of slowed processing, so conversations and reading take more effort; reduced sustained attention, so concentration fails after a shorter period; working-memory difficulty, so instructions and lists slip; word-finding pauses; and a strong sense of mental fatigue after cognitive effort. Objective testing early after concussion often shows less impairment than the person experiences, which is not a contradiction: effortful compensation is itself tiring.
Cognitive demand is harder to reduce than physical demand. Headache improves partly because people naturally avoid what aggravates it, whereas work, childcare and conversation cannot easily be scaled back, so the cognitive system is loaded continuously during recovery. Sleep architecture is commonly disturbed after concussion, and attention and processing speed are the first casualties of poor sleep in anyone. Add the mental effort of compensating and the result is fatigue that persists after the headache has gone.
Sleep is the first target, because nothing else works well while it is disrupted, and it is treatable. Then pacing: cognitive activity in shorter blocks with real breaks, rather than pushing through to a wall, which reliably costs the following day. Reducing simultaneous demands helps more than people expect, since divided attention is disproportionately affected. Aerobic exercise below the symptom threshold benefits cognition as well as recovery generally. Screen work is reintroduced gradually rather than avoided. Caffeine and alcohol both merit review.
Cognitive symptoms that plateau and then fail to improve beyond about a month deserve a specific search rather than more time. Depression and anxiety produce exactly this picture and are common after concussion. Sleep apnoea may have been present beforehand and become apparent now. Medication, including some prescribed for headache or sleep, contributes. Untreated vestibular symptoms cost attention continuously. Where the picture does not fit, formal neuropsychological assessment is arranged rather than performed at these offices.
Clinical Neurology Specialists has been physician-owned since 1998, when Leo Germin, M.D., FAANEM founded it. Five board-certified neurologists and four advanced practice providers see patients at the Las Vegas and Henderson offices, each with its own AANEM-accredited electrodiagnostic laboratory.
Clinical Neurology Specialists is an adult outpatient neurology practice for patients 18 and older. The practice performs no surgery and operates no imaging suite, infusion suite or interventional pain programme, and provides no emergency or inpatient care.
Physician-reviewed. Reviewed by the physicians of Clinical Neurology Specialists — board-certified neurologists, AANEM-accredited electrodiagnostic laboratories, physician-owned since 1998. Reviewed 1 August 2026. This article is general education for adults 18 and older and is not a substitute for a consultation.
Sources and further reading: MedlinePlus: concussion; MedlinePlus: traumatic brain injury; MedlinePlus, National Library of Medicine.
Adults 18 and older, at the Las Vegas and Henderson offices. Call 702-804-1212 or request an appointment online.