Does Process-Specific Slowing Account for Cognitive Deficits in Lyme Disease?

Long-Term Sequelae and Health-Related Quality of Life Associated With Lyme Disease: A Systematic Review

Lyme disease (LD) is the most commonly reported vector-borne disease, but its clinical consequences remain uncertain. We conducted a systematic review of the long-term sequelae and health-related quality of life (HRQoL) associated with LD in North America and Europe. We performed searches in 6 electronic databases up to December 2018 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, including observational studies reporting long-term sequelae, HRQoL, and prognostic factors. We included 46 studies, published between 1994 and 2019. Based on 21 studies reporting attributable outcomes, higher proportions of sequelae reported from exposed patients were: neck pain, myalgia, arthralgia, paresthesia, sleep disorder, poor appetite, and concentration difficulties. Patients with PTLDS reported impaired HRQoL compared to the general US population. Included studies were highly heterogeneous in terms of study design, settings, patient characteristics, and quality. Patients with LD are more likely to report nonspecific long-term sequelae, especially those experiencing persistent symptoms posttreatment. Opportunities exist for prospective longitudinal studies to better understand LD outcomes.

Cognitive Decline in Post-treatment Lyme Disease Syndrome

OBJECTIVE

Patient-reported cognitive complaints are common in those with post-treatment Lyme disease syndrome (PTLDS). Objective evidence of cognitive impairment in this population is variable in part due to methodological variability in existing studies. In this study, we sought to use a systematic approach to characterizing PTLDS based on the most current consensus diagnosis. We further examined PTLDS-related cognitive decline, operationalized as a significant decline in cognitive test performance relative to premorbid cognitive ability.

METHOD

We enrolled a case series of 124 patients with confirmed PTLDS defined by Infectious Diseases Society of America-proposed case definition. Cognitive functioning was evaluated using standardized neuropsychological measures.

RESULTS

The majority (92%) of participants endorsed some level of cognitive difficulty, yet 50% of the sample showed no statistically or clinically significant cognitive decline, 26% of the sample evidenced significant cognitive decline on measures of memory and variably on measures of processing speed, and 24% of the sample were excluded from analyses due to suboptimal test engagement.

CONCLUSIONS

The current findings are consistent with the literature showing that the most robust neurocognitive deficit associated with PTLDS is in verbal memory and with variable decline in processing speed. Compared to population normative comparison standards, PTLDS-related cognitive decline remains mild. Thus, further research is needed to better understand factors related to the magnitude of subjective cognitive complaints as well as objective evidence of mild cognitive decline.

European neuroborreliosis: neuropsychological findings 30 months post-treatment

BACKGROUND

The aim of this study was to compare neuropsychological (NP) functioning in patients with Lyme neuroborreliosis (LNB) 30months after treatment to matched controls.

METHODS

We tested 50 patients with LNB and 50 controls with the trail-making test (TMT), Stroop test, digit symbol test, and California Verbal Learning test (CVLT). A global NP sumscore was calculated to express the number of low scores on 23 NP subtasks.

RESULTS

Mean scores were lower amongst LNB-treated patients than amongst controls on tasks assessing attention/executive functions: (Stroop test 4: 77.6 vs. 67.0, P=0.015), response/processing speed (TMT 5: 23.4 vs. 19.2, P=0.004), visual memory (digit symbol recall: 6.6 vs. 7.2, P=0.038), and verbal memory (CVLT list B: 4.68 vs. 5.50, P=0.003). The proportion of patients and controls with NP sumscores within one SD from the mean in the control group (defined as normal) and between one and two SD (defined as deficit) were similar, but more LNB-treated patients than controls had a sumscore more than two SD from the mean (defined as impairment) (8 vs. 1, P=0.014).

CONCLUSIONS

As a group, LNB-treated patients scored lower on four NP subtasks assessing processing speed, visual and verbal memory, and executive/attention functions, as compared to matched controls. The distribution of NP dysfunctions indicates that most LNB-treated patients perform comparable to controls, whilst a small subgroup have a debilitating long-term course with cognitive problems.

Memory and executive functions in adolescents with posttreatment Lyme disease

Although adults with late stage posttreatment Lyme disease often experience difficulties in memory, little is known about the relationship between cognition and Lyme disease in children and adolescents. Twenty-five adolescents with late stage posttreatment Lyme disease (symptoms > 6 months) and 25 participants without Lyme disease (matched on gender, IQ, age, socioeconomic status) were assessed for neuropsychological functioning, depression, school functioning, and predisease academic achievement. The Lyme group had significant deficits in cognition (short-term visual memory, short-term and delayed verbal memory, all forms of recognition memory), as well as worse attendance, grades, and subjective reports of memory problems, without differing in predisease achievement or depression. Deficits in visual memory exceeded deficits in verbal memory-a striking difference from what is reported in adults. These results reveal that adolescents with a history of treated Lyme disease are at risk for long-term problems in cognition and school functioning.

Certains symptômes cliniques aspécifiques ont-ils une origine borrélienne?

Chronic manifestations (knee arthritis, encephalomyelitis, axonal polyneuropathy) may occur in the late phase of Lyme disease. Contrasting with such well-defined manifestations, the "post-Lyme syndrome" includes symptoms such as fatigue, algia, malaise, cognitive disorders, after treatment of a documented Lyme disease. The analysis of clinical, neuropsychological, bacteriological, immunological, epidemiological, quality of life, and treatment data does not support the reality of such a syndrome. Moreover, no physiopathological data can relate Borrelia infection to such symptoms in patients without previously documented Lyme disease symptoms but who are seropositive (or even sometimes without serodiagnosis as for instance in the Munchausen by proxy, or Gulf war syndromes).

WAIS-III and WMS-III performance in chronic Lyme disease

There is controversy regarding the nature and degree of intellectual and memory deficits in chronic Lyme disease. In this study, 81 participants with rigorously diagnosed chronic Lyme disease were administered the newest revisions of the Wechsler Adult Intelligence Scale (WAIS-III) and Wechsler Memory Scale (WMS-III), and compared to 39 nonpatients. On the WAIS-III, Lyme disease participants had poorer Full Scale and Performance IQ's. At the subtest level, differences were restricted to Information and the Processing Speed subtests. On the WMS-III, Lyme disease participants performed more poorly on Auditory Immediate, Immediate, Auditory Delayed, Auditory Recognition Delayed, and General Memory indices. Among WMS-III subtests, however, differences were restricted to Logical Memory (immediate and delayed) and Family Pictures (delayed only), a Visual Memory subtest. Discriminant analyses suggest deficits in chronic Lyme are best characterized as a combination of memory difficulty and diminished processing speed. Deficits were modest, between one-third and two-thirds of a standard deviation, consistent with earlier studies. Depression severity had a weak relationship to processing speed, but little other association to test performance. Deficits in chronic Lyme disease are consistent with a subtle neuropathological process affecting multiple performance tasks, although further work is needed to definitively rule out nonspecific illness effects.

Neuropsychological functioning in chronic Lyme disease

Lyme disease is currently the most common vector-borne illness in the United States. The disease is multisystemic, and chronic disease, in particular, may be associated with neuropsychological deficits. However, to date, only a few empirical studies exist, which examine the neuropsychological sequelae associated with chronic Lyme disease. A review of the literature shows that the deficits observed in adults with chronic Lyme disease are generally consistent with the deficits that can be seen in processes with primarily frontal systems involvement. These observations are generally consistent with neuroradiologic findings. The clinical presentation in chronic Lyme disease and the nature of the neuropsychological deficits are discussed, as are several central issues in understanding neuropsychological functioning in chronic Lyme disease, such as the impact of chronic illness, response to treatment, and the relationship between neuropsychological performance and depression, fatigue, and neurological indicators of disease.