Who should undergo a comprehensive cognitive assessment after a stroke? A cognitive risk score.

OBJECTIVE: To validate the ability of a specifically developed cognitive risk score to identify patients at risk of poststroke neurocognitive disorders (NCDs) who are eligible for a comprehensive cognitive assessment. METHODS: After assessing 404 patients (infarct 91.3%) in the Groupe de Réflexion pour l'Evaluation Cognitive VASCulaire (GRECogVASC) cross-sectional study with the National Institute of Neurological Disorders and Stroke-Canadian Stroke Network battery 6 months after stroke, we used multivariable logistic regression and bootstrap analyses to determine factors associated with NCDs. Independent, internally validated factors were included in a cognitive risk score. RESULTS: Cognitive impairment was present in 170 of the 320 patients with a Rankin Scale score ≥1. The backward logistic regression selected 4 factors (≥73% of the permutations): NIH Stroke Scale score on admission ≥7 (odds ratio [OR] 2.73, 95% confidence interval [CI] 1.29-4.3, p = 0.005), multiple strokes (OR 3.78, 95% CI 1.6-8, p = 0.002), adjusted Mini-Mental State Examination (MMSEadj) score ≤27 (OR 6.69, 95% CI 3.9-11.6, p = 0.0001), and Fazekas score ≥2 (OR 2.34, 95% CI 1.3-4.2, p = 0.004). The cognitive risk score computed with these 4 factors provided good calibration, discrimination (overoptimism-corrected C = 0.793), and goodness of fit (Hosmer-Lemeshow test p = 0.99). A combination of Rankin Scale score ≥1, cognitive risk score ≥1, and MMSEadj score ≥21 selected 230 (56.9%) of the 404 patients for a comprehensive assessment. This procedure yielded good sensitivity (96.5%) and moderate specificity (43%; positive predictive value 0.66, negative predictive value 0.91) and was more accurate (p ≤ 0.03 for all) than the sole use of screening tests (MMSE or Montréal Cognitive Assessment). CONCLUSION: The GRECogVASC cognitive risk score comprises 4 easily documented factors; this procedure helps to identify patients at risk of poststroke NCDs who must therefore undergo a comprehensive assessment. CLINICALTRIALSGOV IDENTIFIER: NCT01339195.

Prevalence of Poststroke Neurocognitive Disorders Using National Institute of Neurological Disorders and Stroke-Canadian Stroke Network, VASCOG Criteria (Vascular Behavioral and Cognitive Disorders), and Optimized Criteria of Cognitive Deficit.

BACKGROUND AND PURPOSE: The prevalence of poststroke neurocognitive disorder (NCD) has yet to be accurately determined. The primary objective of the present study was to optimize operationalization of the criterion for NCD by using an external validity criterion. METHODS: The GRECOG-VASC cohort (Groupe de Réflexion pour l'Évaluation Cognitive Vasculaire) of 404 stroke patients with cerebral infarct (91.3%) or hemorrhage (18.7%) was assessed 6 months poststroke and 1003 healthy controls, with the National Institute of Neurological Disorders and Stroke-Canadian Stroke Network standardized battery. Three dimensions of the criterion for cognitive impairment were systematically examined by using the false-positive rate as an external validity criterion. Diagnosis of mild and major NCD was based on the VASCOG criteria (Vascular Behavioral and Cognitive Disorders). The mechanisms of functional decline were systematically assessed. RESULTS: The optimal criterion for cognitive impairment was the shortened summary score (ie, averaged performance for action speed, executive functions, and language) because it was associated with the highest (P=0.0001) corrected true-positive rate (43.5%) and a false-positive rate ≤5%. Using this criterion, the mean (95% confidence interval) prevalence of poststroke NCD was 49.5% (44.6-54.4), most of which corresponded to mild NCD (39.1%; 95% confidence interval, 34.4-43.9) rather than dementia (10.4%; 95% confidence interval, 7.4-13.4). CONCLUSIONS: This study is the first to have optimized the operationalization of the criterion for poststroke cognitive impairment. It documented the prevalence of poststroke NCD in the GRECOG-VASC cohort and showed that mild cognitive impairment accounts for 80% of the affected patients. Finally, the method developed in the present study offers a means of harmonizing the diagnosis of NCD. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01339195.

Presence of crystalline inclusions in the peripheral nerve of a patient with IgA lambda monoclonal gammopathy of undetermined significance.

Association of a peripheral neuropathy with an IgA monoclonal gammopathy of undetermined significance (MGUS) is not commonly observed and is sometimes considered as coincidental. We present a case in which the nerve biopsy revealed the presence of crystalline inclusions in the endoneurium, a very unusual finding. A 75-year-old man complained of paresthesiae in both feet and unsteady gait for 6 months. He had no weakness, but deep tendon reflexes were absent and vibratory sensation distally diminished in both legs. An IgA lambda MGUS was evidenced in his serum at 10.2 g/L with 7% plasma cells in his bone marrow and no lytic lesion at skeletal examination. A superficial peroneal nerve biopsy was performed and showed numerous crystalline inclusions in the endoneurium. These were located in the cytoplasm of macrophagic histiocytes or free in the vicinity of nerve fibers. There was also a marked loss of myelinated nerve fibers and several "onion bulb" formations surrounding either isolated remyelinating fibers or small clusters of remyelinating fibers. Such crystalline inclusions have mainly been observed in the cytoplasm of plasma cells in cases of multiple myeloma, and correspond to non-secreted IgA or IgG immunoglobulins with a kappa or rarely lambda light chain. Such inclusions have also been reported in the cytoplasm of the epithelial cells from corneal fragments, in patients with multiple myeloma or IgG MGUS, and in the tubular cells from the kidney of patients with multiple myeloma and a nephrotic syndrome. In the literature, there is only one very briefly mentioned case of neuropathy associated with a myeloma and with crystalline inclusions present in the epineurium. Thus, in dysglobulinemic neuropathy, nerve fibers can be damaged by three kinds of interstitial deposits, easily identified by immunohistochemistry and at ultrastructural examination: the well known amyloid fibrils, granulo-fibrillar deposits and also crystalline inclusions.