Continuing our series, Dr Marc Kingsley and Dr Claire Doyle discuss presentations of cognitive impairment after Covid-19
Cognitive impairment linked to long Covid-19
Research into the impact of long Covid on mental health and cognitive functioning is still emerging, but adverse effects are commonly reported and may still be underestimated.1
Early findings indicate these effects include deficits in attention, mental processing speed, memory and executive function.2 A recent review described ‘brain fog’ as a commonly reported and debilitating symptom,3 and a large-scale online study reported Covid-related deficits in reasoning, problem solving, spatial planning and target detection.4
What lies behind these changes?
Patients experiencing cognitive difficulties as a long-term effect of Covid are a diverse group with a number of potential underlying factors. While neuropathological processes may be relevant for some, reversible biopsychosocial variables are also important and can inform a cautious but reassuring message to patients about the possibility of improvement in symptoms over time.
Potential underlying causes of cognitive changes in long Covid
More than a third of patients experience fatigue in the acute phase of Covid-19.5 This often persists in long Covid and likely contributes to cognitive difficulties.
Sleep disturbance, including sleep apnoea, ongoing pain, side- effects of medications and the persistent, preoccupying experience of shortness of breath, may impact on cognitive efficiency.
Depression, anxiety and trauma reactions are common among Covid patients, and are associated with psychological processes that limit attentional resources and reduce cognitive efficiency.
Covid-19 is thought to affect the central nervous system, through various mechanisms such as breaches of the blood-brain barrier by the virus, infection of neurons via the olfactory nerve and damage from hypoxia and inflammatory processes.6
A small number of patients will have ischaemic stroke or other neurological conditions, such as encephalopathy, encephalitis or hypoxic brain damage.7 Together with the known impact of ICU treatment on cognition, this means some patients presenting to primary care are likely to have neurological changes that impact on cognition.
Assessment of cognitive changes
It is important to assess potential cognitive changes, particularly in patients recovering from severe Covid-19, who seem to be at increased risk of developing neurological symptoms,8,9 and older adults with risk factors for dementia. In the latter, it is thought Covid-19 may accelerate or unmask a degenerative condition,6 or that new Covid-related neuropathology may mimic a degenerative condition.
Ask all patients presenting to primary care with long Covid symptoms about cognitive problems and symptoms of anxiety or depression. Use the Covid-19 Yorkshire Rehabilitation Screening Tool to enquire about cognitive problems.10
This includes the following two questions:
- Since your illness, have you had new or worsened difficulty with:
– Concentrating? Yes/No
– Short-term memory? Yes/No
The 6-CIT,11 or the FreeCog,12 can also be used if dementia is suspected; if no degenerative condition is suspected but the patient reports subjective cognitive complaints, use the Montreal Cognitive Assessment (MoCA).13 Very brief validated tools for the initial assessment of depression and anxiety include the PHQ-2 and GAD-2.
First rule out other conditions or medical variables that might explain the cognitive difficulties.
Reassure the patient that their symptoms are real and common following Covid-19. Explain that approximately 10% of people experience long Covid after acute infection14 and that ‘brain fog’ as part of this may be present for a number of reasons, many of which are reversible. Advise that most people will recover with no long-term impact on their memory and concentration. Offer to create a management plan together. This plan could include:
- Watchful waiting. Particularly when the patient has not reached 12 weeks post-Covid, offer telephone reviews to monitor progress. Enquire about times when the difficulties were absent or less troublesome as well as asking about symptoms. This may help to establish the relationships between variables, such as fatigue and cognitive problems, and inform the management plan.
- Offer mood screening at any point, ideally at the initial consultation and at each follow-up.
- Offer the patient cognitive screening from 12 weeks – before this stage the scores may reflect acute and fluctuating Covid-19 symptoms and general malaise. Do not repeat the same cognitive
screen within a short time frame as familiarity can inflate the score and obscure deficits.
- Signpost to relevant self-management advice from NHS Choices based on the patient’s broader presenting problems. Signpost to the NHS Your Covid Recovery website for information and advice
- Consider onward referrals, as needed. These may include:
– Your local Long Covid service
– Improving Access to Psychological Therapies service, for mild to moderate symptoms of depression, anxiety and trauma symptoms
– Memory services where a dementia is suspected
– Community rehabilitation or neurorehabilitation teams when cognitive difficulties are associated with significant functional and/or occupational limitations
– Neurology services where neuropathological sequelae of Covid-19 infection are suspected following a neurological examination.
Dr Marc Kingsley is a consultant clinical psychologist and Dr Claire Doyle is a consultant clinical neuropsychologist at North East London NHS Foundation Trust
- Taquet M et al. Bidirectional associations between COVID-19 and psychiatric disorder. Lancet Psychiatry 2021;8:130-140
- Beaud V et al. Pattern of cognitive deficits in severe COVID-19. J Neurol Neurosurg Psychiatry 2021;92:567–568
- Crook H et al. Long covid – mechanisms, risk factors, and management. BMJ 2021;374:n1648
- Hampshire A et al. Cognitive deficits in people who have recovered from Covid-19. Lancet EClinicalMedicine 2021;39:10144
- Rogers J et al. Neurology and neuropsychiatry of Covid-19. J Neurol Neurosurg Psychiatry 2021;92:932–941
- Ritchie K et al. The cognitive consequences of the COVID-19 epidemic: collateral damage? Brain Commun 2020;2:fcaa069
- Varatharaj A et al. Neurological and neuropsychiatric complications of Covid-19 in 153 patients. Lancet Psychiatry 2020;7:875–882.
- Mao L et al. Neurologic manifestations of hospitalised patients with coronavirus disease in 2019 in Wuhan, China. JAMA Neurol 2020;77:683-690
- British Psychological Society. Meeting the psychological needs of people recovering from severe coronavirus (Covid-19). Guidance. London: BPS, 2020.
- Sivan M et al. Assessing long-term rehabilitation needs in Covid-19 survivors using a telephone screening tool (C-19 YRS tool). Adv Clin Neurosci Rehabil 2020; 19:14-17
- NICE. Dementia: assessment, management and support for people living with dementia and their carers. Guidance. London: NICE, 2018.
- Burns A et al. A novel hybrid scale for the assessment of cognitive and executive function: The Free-Cog. Int J Geriatr Psychiatry 2021;36:566-572
- Nasreddine Z et al. The Montreal Cognitive Assessment, MoCA. J Am Geriatr Soc 2005;53:695-699
- Greenhalgh T et al. Management of post-acute covid-19 in primary care. BMJ 2020;370:m3026.