The neuropsychological examination of naming in Lyme borreliosis

Abstract

Although subjective complaints of word finding and naming difficulties are commonly reported by patients with Lyme Borreliosis (LB), the existence and nature of these disturbances has not been thoroughly investigated. Forty-nine patients with LB and 43 healthy controls who were comparable with respect to age, gender distribution, level of education, and premorbid IQ were employed in the present stud. Subjects completed a symptom questionnaire and the Cognitive Affective Index (CAI) of the Beck Depression Inventory. They were subsequently administered a neuropsychological test battery which included the North American Adult Reading Test (NAART), the Boston Naming Test (BNT), the Controlled Oral Word Association Test (COWAT), and a series of category naming tasks. The California Verbal Learning Test (CVLT) and Digit Span were incorporated into the test protocol to determine their association with measures of naming.;Results revealed that complaints of word finding abilities were present in 58% of the patients whose diagnostic work ups were positive for LB. A significant proportion of these patients, 57%, additionally complained of impairments in memory and retrieval. Lower mean scores were observed on the BNT, CVLT, and semantic category indexes. Twenty three percent of the LB sample exhibited BNT scores in the "impaired" range. Lyme patients required more cues than normal controls on the BNT, yet demonstrated a higher response accuracy rate when provided with phonemic than semantic cues. No semantic fluency scores in the LB group were correlated with a measure of retrieval whereas phonemic fluency was associated with a measure of attention. There was no relationship between naming scores and depression. LB subjects exhibited impairments in word finding abilities that appear to be due to semantic erosion with secondary effects on lexical access. Given the numerous cognitive deficits previously found in LB patients coupled with today's findings of naming impairments, it appears that Lyme disease can result in diffuse neuropsychological and neuropathological dysfunction.