This study aims to elucidate the nature of cognitive deficits caused by intracranial tumors, as well as to examine how a surgical operation of the tumor may affect tumor-induced cognitive deficits. The patient group included 43 individuals with meningioma or low-grade glioma admitted to a surgical operation of the tumor. Neuropsychological examination was conducted preoperatively, as well as three and 12 months postoperatively. The control group comprised 31 healthy subjects. In the tumor patients, preoperative cognitive performance was compromised in several cognitive domains as compared to the controls. The tumor patients with frontal and large tumors showed impairment virtually across all cognitive domains. Postoperatively, the cognitive performance of the meningioma and the small tumor group improved in all domains, with the performance of the low-grade glioma group and the large tumor group reflecting more modest cognitive improvement. Most of this improvement did not emerge until the 12 months follow-up. Cognitive impairment due to an intracranial tumor is diffuse affecting most cognitive domains. Cognitive recovery after the surgery is more noticeable in patients with meningiomas and small tumors, and the recovery will require a minimum of one year time-wise. This evidence is of significant value when planning both clinical treatment and rehabilitation of intracranial tumor patients.
Intracranial tumors commonly result in both neurological and neuropsychological deficits. Namely, infiltration and pressure from tumoral tissue disturb the normal functionality of the brain, which in turn is associated with a deterioration of several cognitive functions, such as those pertaining to memory, visuospatial, verbal and more broadly, executive operations [
Tumors located in the dominant hemisphere of the brain, usually the left hemisphere (LH), are commonly linked to aphasic disorders as well as other forms of verbal deficits [
The histological type of the tumor is linked to the severity of the cognitive impairment, with higher-grade tumors being associated with more severe cognitive impairment than lower-grade tumors [
In order to obtain a reliable estimate of how the intracranial tumor itself, as well as its treatment methods, influence cognitive functions, neuropsychological assessment must be conducted both pre- and post-operatively [
Currently, there is only a handful of post-treatment studies in which the effects of the tumor treatment on cognitive functions has been studied systematically, in which a control group has been included, as well as a more extensive neuropsychological assessment battery in addition to mere screening tests, such as the Mini-Mental State Examination (MMSE) [
The study included all patients with meningioma or glioma treated with partial or complete resection of the tumor at the Clinic of Neurosurgery in Oulu University Hospital during two years. Patients were excluded from the study if their chronological age was either under 16 or over 75 years, they had tumor metastases or their physical condition was too weak hampering the participation in neuropsychological examination. After these criteria were met, the neuropsychological examination was conducted for 43 patients. Patients were assessed with a neuropsychological examination preoperatively, as well as three and 12 months postoperatively. Two patients dropped out before the three-month follow-up due to death. The enrolled patients did not receive any neuropsychological rehabilitation. The control group comprised 31 volunteers with no diagnosed neurological diseases age-matched to the clinical patients. The control group was administered an identical neuropsychological assessment to the tumor patients with the exception of the follow-up procedure, which was omitted. In addition, to screen for global cognitive impairment, those volunteers who were over 55 years and/or retired from work were submitted to a cognitive screening test. For this purpose, the MMSE [
Neurological examination was carried out by a physician. The histological grade of tumors was defined according to the World Health Organization (WHO) classification of tumors [
Patients (n = 43) | Controls (n = 31) | |
---|---|---|
Age (mean, SD)* | 46.3 ± 12.5 | 45.6 ± 19.0 |
Sex (M/F)* | 14/29 | 10/21 |
Location of tumor: | ||
L/R/B | 21/14/5** | - |
A/P/UD | 24/13/6 | - |
Tumor diagnosis: | - | |
Meningioma | 25 | |
Grade I-II glioma | 18 | |
Tumor volume (median, IQR in ml) | 31.7 (10.8 - 58.8) | - |
Treated with radiation therapy | - | |
Meningioma | 2 | |
Grade I-II glioma | 15 | |
Treated with chemotherapy | - | |
Meningioma | 0 | |
Grade I-II glioma | 3 |
Abbreviations: SD = standard deviation; M = male; F = female; L = left; R = right; B = bilateral; A = anterior; P = posterior; UD = undefined; IQR = interquartile range. *The patient and the control group did not differ significantly in age (Mann-Whitney U Test; U = 619.5, p = 0.61) or gender (Chi-square test; χ2 = 0.01, p = 0.98). **CT or MRI images for sufficiently accurate analysis of tumor volume and lateral location were not available for three patients.
the CT or MRI images, and each tumor was then classified according to size (small/large) on the basis of the median (small < 31, 70 ml ≤ large) of the tumor volume. CT was used predominantly and the neuroradiologist was consulted.
Verbal functions were assessed using the Similarities subtest of the Wechsler Adult Intelligence Scale (WAIS) [
Statistical analyses were conducted using non-parametric tests due to the variables failing to meet the assumptions of normality. Medians and quartiles were used as descriptive values. If the subject failed to complete the Stroop test or the Serial Subtraction test, the missing values were replaced with the maximum value from the sample, in order to include an estimate for cases representing weak performance into the analyses. The comparisons between the tumor groups and the controls were analyzed utilizing the two-tailed Kruskal-Wallis test, while the comparisons within the tumor groups at the follow-up were analyzed with the Wilcoxon Signed-Rank test. The statistical significance was set at p < 0.05 for both tests.
The patient group underwent the neuropsychological assessment preoperatively, as well as three and 12 months postoperatively, while the control group underwent the assessment once. Results of the preoperative neuropsychological assessment are displayed in
In general terms, the clinical patients showed significantly weaker performance in nearly all cognitive domains as compared to the controls. Comparisons between the tumor groups and the controls are presented in
Relative to the controls, the anterior tumor group performed at a significantly lower level in all cognitive domains, whereas the posterior tumor group showed significant deficits in visuospatial, attentional, and delayed memory functions. Both the LH and RH tumor groups demonstrated significantly lower levels of
Group | Simil | Block | Word tot | Word del | Story imm | Story del | Serial | Stroop | |
---|---|---|---|---|---|---|---|---|---|
MNG | (n = 25) | 17.4 ± 5.3 (5 - 25) | 24.0 ± 5.3 (8 - 47) | 38.5 ± 8.8 (9 - 48) | 6.21 ± 2.6 (0 - 10) | 8.0 ± 3.4 (3 - 16) | 10.3 ± 4.0 (2 - 17) | 160.9 ± 123.0 (25 - 400) | 249.6 ± 171.1 (76 - 530) |
LGG | (n = 18) | 16.7 ± 3.6 (10 - 23) | 29.8 ± 12.4 (6 - 47) | 40.0 ± 6.1 (28 - 49) | 6.4 ± 2.3 (0 - 10) | 7.2 ± 3.9 (2 - 16) | 9.3 ± 4.0 (1 - 16) | 140.1 ± 119.3 (30 - 400) | 210 ± 156.0 (82 - 530) |
Small | (n = 20) | 17.5 ± 5.0 (5 - 23) | 26.4 ± 9.7 (10 - 47) | 40.0 ± 9.4 (9 - 49) | 6.2 ± 2.8 (0 - 10) | 8.1 ± 4.2 (2 - 16) | 11.1 ± 4.3 (2 - 17) | 150.4 ± 125.9 (25 - 400) | 228.6 ± 168.9 (76 - 530) |
Large | (n = 20) | 16.7 ± 4.5 (8 - 25) | 26.0 ± 13.1 (6 - 47) | 37.7 ± 6.0 (27 - 47) | 6.4 ± 2.3 (0 - 10) | 7.1 ± 3.0 (2 - 11) | 8.6 ± 3.7 (1 - 16) | 162.3 ± 123.4 (25 - 400) | 232.4 ± 159.5 (98 - 530) |
LH | (n = 21) | 16.8 ± 5.3 (5 - 23) | 28.2 ± 12.5 (8 - 47) | 37.7 ± 9.5 (9 - 49) | 6.4 ± 2.7 (0 - 10) | 7.3 ± 3.9 (2 - 16) | 10.0 ± 4.1 (3 - 17) | 164.7 ± 135.6 (25 - 400) | 213.1 ± 162.2 (76 - 530) |
RH | (n = 14) | 17.4 ± 4.2 (11 - 25) | 23.4 ± 10.8 (6 - 47) | 40.0 ± 5.6 (28 - 48) | 6.4 ± 2.6 (0 - 10) | 7.9 ± 4.0 (2 - 16) | 9.7 ± 4.4 (1 - 16) | 122.4 ± 101.0 (25 - 400) | 225.5 ± 147.4 (82 - 530) |
Anterior | (n = 24) | 16.0 ± 5.2 (5 - 23) | 23.3 ± 9.7 (6 - 47) | 38.6 ± 8.7 (9 - 48) | 6.3 ± 2.5 (0 - 9) | 7.4 ± 4.0 (2 - 16) | 9.4 ± 4.4 (1 - 17) | 162.8 ± 124.5 (25 - 400) | 242.4 ± 163.1 (76 - 530) |
Posterior | (n = 13) | 18.7 ± 3.3 (12 - 24) | 29.8 ± 12.1 (8 - 47) | 38.9 ± 7.1 (29 - 48) | 6.2 ± 2.7 (0 - 10) | 7.8 ± 3.1 (2 - 11) | 9.9 ± 3.5 (4 - 16) | 124.6 ± 98.2 (34 - 400) | 218.9 ± 179.1 (82 - 530) |
Controls | (n = 31) | 19.4 ± 2.6 (11 - 25) | 37.8 ± 9.1 (18 - 48) | 41.7 ± 4.0 (33 - 50) | 7.8 ± 2.0 (3 - 10) | 9.9 ± 3.8 (3 - 19) | 13.4 ± 3.8 (5 - 21) | 55.5 ± 20.4 (27 - 94) | 120.9 ± 26.0 (79 - 186) |
Abbreviations: Simil = WAIS Similarities; Block = WAIS Block Design; Word Tot = Word List Recall Total score; Word del = Word List Recall Delayed Recall; Story imm = The Babcock story immediate recall; Story del = The Babcock Story delayed recall; Serial = Serial Seven Subtraction Test time; Stroop = Stroop Test time; MNG = Meningioma; LGG = Low-grade Glioma (grade I-II); LH = Left Hemisphere; RH = Right Hemisphere.
Group | Simil | Block | Word tot | Word del | Story imm | Story del | Serial | Stroop | |
---|---|---|---|---|---|---|---|---|---|
MNG | 3 mo | 17.4 ± 5.0 (2 - 23) | 28.2 ± 10.2 (14 - 47) | 37.6 ± 8.5 (11 - 47) | 7.2 ± 2.8 (0 - 10) | 8.9 ± 4.8 (1 - 19) | 10.9 ± 5.4 (0 - 19) | 139.6 ± 119.8 (25 - 400) | 206.8 ± 156.4 (65 - 530) |
12 mo | 18.0 ± 4.4 (6 - 23) | 30.5 ± 8.9 (12 - 48) | 40.3 ± 7.9 (19 - 49) | 7.4 ± 2.1 (1 - 10) | 9.5 ± 4.6 (0 - 20) | 11.8 ± 5.0 (0 - 20) | 128.8 ± 127.9 (26 - 400) | 194.6 ± 158.8 (65 - 530) | |
LGG | 3 mo | 16.8 ± 3.7 (7 - 21) | 30.1 ± 13.6 (8 - 48) | 39.5 ± 7.2 (27 - 50) | 6.9 ± 2.3 (0 - 10) | 9.4 ± 4.3 (1 - 18) | 10.2 ± 5.0 (0 - 17) | 126.3 ± 124.3 (27 - 400) | 194 ± 138.9 (92 - 530) |
12 mo | 18.1 ± 3.7 (9 - 22) | 34.1 ± 10.2 (18 - 48) | 40.8 ± 6.7 (26 - 50) | 7.6 ± 1.6 (4 - 10) | 10.4 ± 4.6 (3 - 17) | 10.8 ± 4.2 (1 - 16) | 105.9 ± 104.6 (27 - 400) | 210.1 ± 156.8 (84 - 530) | |
Small | 3 mo | 17.8 ± 3.9 (8 - 23) | 30.0 ± 10.7 (14 - 48) | 38.6 ± 8.7 (11 - 50) | 7.3 ± 2.5 (0 - 10) | 9.6 ± 5.2 (1 - 19) | 11.0 ± 5.4 (0 - 19) | 127.8 ± 115.1 (25 - 400) | 192.6 ± 155.3 (65 - 530) |
12 mo | 18.4 ± 3.5 (11 - 23) | 31.2 ± 9.3 (12 - 47) | 42.3 ± 6.7 (28 - 50) | 7.6 ± 2.1 (1 - 10) | 10.1 ± 5.1 (1 - 20) | 12.1 ± 5.0 (0 - 20) | 117.2 ± 126.5 (26 - 400) | 187.5 ± 154.7 (65 - 530) | |
Large | 3 mo | 16.5 ± 5.2 (2 - 22) | 27.9 ± 13.2 (8 - 48) | 37.5 ± 7.3 (22 - 48) | 6.8 ± 3.0 (0 - 10) | 8.4 ± 3.9 (2 - 18) | 9.8 ± 5.1 (0 - 17) | 148.3 ± 131.7 (49 - 400) | 220.1 ± 147.5 (100 - 530) |
12 mo | 17.9 ± 4.8 (6 - 23) | 32.7 ± 10.4 (16 - 48) | 37.9 ± 7.7 (19 - 49) | 7.2 ± 1.7 (4 - 10) | 9.7 ± 4.3 (0 - 16) | 10.3 ± 4.3 (0 - 16 | 129.2 ± 116.7 (44 - 400) | 227.2 ± 164.1 (104 - 530) | |
LH | 3 mo | 17.0 ± 5.1 (2 - 23) | 31.2 ± 12.7 (12 - 48) | 37.1 ± 9.6 (11 - 49) | 7.1 ± 2.8 (0 - 10) | 7.8 ± 4.8 (1 - 19) | 10.0 ± 5.5 (0 - 19) | 133.8 ± 114.0 (27 - 400) | 208.9 ± 147.6 (65 - 530) |
12 mo | 18.4 ± 4.8 (6 - 23) | 31.7 ± 11.6 (12 - 48) | 38.5 ± 7.9 (19 - 49) | 7.4 ± 2.1 (1 - 10) | 9.5 ± 5.5 (0 - 20) | 10.4 ± 5.5 (0 - 20) | 115.6 ± 106.1 (26 - 400) | 223.7 ± 172.2 (65 - 530) | |
RH | 3 mo | 17.1 ± 4.3 (7 - 22) | 25.9 ± 11.4 (8 - 48) | 39.2 ± 6.1 (27 - 50) | 6.9 ± 2.8 (0 - 10) | 10.5 ± 4.3 (4 - 18) | 10.5 ± 5.0 (0 - 17) | 128.6 ± 131.4 (25 - 400) | 170.2 ± 115.1 (92 - 530) |
12 mo | 18.2 ± 3.7 (11 - 22) | 32.3 ± 7.1 (24 - 48) | 42.2 ± 6.7 (26 - 50) | 7.3 ± 1.7 (4 - 10) | 10.5 ± 3.7 (5 - 17) | 12.3 ± 2.6 (8 - 16) | 122.6 ± 137.0 (28 - 400) | 145.2 ± 62.2 (84 - 295) | |
Anterior | 3 mo | 16.3 ± 5.2 (2 - 23) | 26.9 ± 11.3 (8 - 48) | 36.8 ± 8.2 (11 - 49) | 6.7 ± 3.0 (0 - 10) | 8.6 ± 4.3 (1 - 19) | 9.5 ± 5.5 (0 - 19) | 154.0 ± 131.0 (25 - 400) | 244.9 ± 178.1 (65 - 530) |
12 mo | 17.2 ± 4.5 (6 - 23) | 29.0 ± 9.4 (12 - 47) | 39.9 ± 7.5 (19 - 49) | 7.3 ± 2.1 (1 - 10) | 9.2 ± 4.7 (0 - 20) | 10.7 ± 5.3 (0 - 20) | 133.9 ± 129.8 (26 - 400) | 240.9 ± 182.7 (65 - 530) | |
Posterior | 3 mo | 18.3 ± 1.9 (16 - 21) | 31.7 ± 11.4 (16 - 48) | 41.8 ± 7.2 (26 - 50) | 8.0 ± 1.7 (6 - 10) | 10.3 ± 4.7 (3 - 18) | 12.3 ± 3.7 (5 - 17) | 100.0 ± 96.2 (46 - 400) | 134.2 ± 35.9 (92 - 195) |
12 mo | 17.2 ± 4.5 (6 - 23) | 29.0 ± 9.4 (12 - 47) | 39.9 ± 7.5 (19 - 49) | 7.3 ± 2.1 (1 - 10) | 9.2 ± 4.7 (0 - 20) | 10.7 ± 5.3 (0 - 20) | 86.3 ± 100.5 (35 - 400) | 137.3 ± 95.7 (84 - 437) |
Abbreviations: Simil = WAIS Similarities; Block = WAIS Block Design; Word Tot = Word List Recall Total score; Word del = Word List Recall Delayed Recall; Story imm = The Babcock story immediate recall; Story del = The Babcock Story delayed recall; Serial = Serial Seven Subtraction Test time; Stroop = Stroop Test time; MNG = Meningioma; LGG = Low Grade Glioma (grade I-II); LH = Left Hemisphere; RH = Right Hemisphere.
performance relative to controls with only minor exceptions in memory functions. The performance of patients with small tumor volumes was significantly hampered in attentional, visuospatial and memory functions as compared to the controls, albeit not to the same extent as observed for the large tumor group, which performed significantly lower level in all measured cognitive functions and subtests.
The patients with meningiomas performed at a significantly lower level as
Simil | Block | Word tot | Word del | Story imm | Story del | Serial | Stroop | |
---|---|---|---|---|---|---|---|---|
Meningioma (n = 25) | ns | <0.001 | ns | 0.017 | ns | 0.007 | <0.001 | 0.001 |
LGG (n = 18) | 0.005 | 0.021 | ns | 0.034 | 0.033 | 0.002 | 0.001 | ns |
Small (n = 20) | ns | <0.001 | ns | 0.033 | ns | ns | 0.005 | ns |
Large (n = 20) | 0.010 | 0.001 | 0.024 | 0.018 | 0.028 | <0.001 | <0.001 | 0.001 |
LH (n = 21) | ns | 0.006 | ns | 0.050 | 0.032 | 0.004 | <0.001 | 0.036 |
RH (n = 14) | ns | <0.001 | ns | ns | ns | 0.020 | 0.027 | 0.004 |
Anterior (n = 24) | 0.010 | <0.001 | ns | 0.015 | 0.021 | 0.002 | <0.001 | 0.001 |
Posterior (n = 13) | ns | 0.042 | ns | 0.049 | ns | 0.007 | 0.02 | ns |
“ns” indicates no statistically significant difference between the groups on a 0.05 level. Patient groups are classified according to tumor characteristics. Abbreviations: Simil = WAIS Similarities; Block = WAIS Block Design; Word Tot = Word List Recall Total score; Word del = Word List Recall Delayed Recall; Story imm = The Babcock story immediate recall; Story del = The Babcock Story delayed recall; Serial = Serial Seven Subtraction Test time; Stroop = Stroop Test time; LGG = Low-grade Glioma (grade I-II); LH = Left Hemisphere; RH = Right Hemisphere.
compared to the controls in attentional, visuospatial and delayed memory functions, while the group with low-grade gliomas (grade I-II; LGG) showed deficient performance relative to the controls in all cognitive areas with the exception of one subtest in attentional and one subtest in memory functions.
The results of within-patient group comparisons between the preoperative and follow-up assessment of cognitive functions are shown in
At the three-month follow-up, the anterior tumor group showed improvement in visuospatial functions but deterioration in immediate memory functions, while the posterior tumor group demonstrated improvement for immediate memory functions. At the 12-month follow-up, patients with anterior tumors showed further improvement in attentional and memory functions, and the deterioration of immediate memory functions seen at the three-month follow-up did not emerge. In the posterior group, a further improvement in all but verbal functions was seen.
At the three-month follow-up, the patients with small tumor volumes exhibited improvement in visuospatial and memory functions, while those with large
Simil | Block | Word tot | Word del | Story imm | Story del | Serial | Stroop | |
---|---|---|---|---|---|---|---|---|
Meningioma | ns | 0.004 | ns | 0.036 | ns | ns | ns | ns |
LGG | ns | ns | ns | ns | 0.037 | ns | ns | ns |
Small | ns | 0.033 | ns | 0.012 | ns | 0.049 | ns | ns |
Large | ns | ns | ns | ns | ns | ns | ns | ns |
LH | ns | ns | ns | ns | ns | ns | ns | ns |
RH | ns | ns | ns | ns | 0.019 | ns | ns | ns |
Anterior | ns | 0.013 | 0.027 | ns | ns | ns | ns | ns |
Posterior | ns | ns | 0.036 | ns | ns | ns | ns | ns |
“ns” indicates no statistically significant difference between the groups on a 0.05 level. Abbreviations: Simil = WAIS Similarities; Block = WAIS Block Design; Word Tot = Word List Recall Total score; Word del = Word List Recall Delayed Recall; Story imm = The Babcock story immediate recall; Story del = The Babcock Story delayed recall; Serial = Serial Seven Subtraction Test time; Stroop = Stroop Test time; LGG = Low-grade Glioma (grade I-II); LH = Left Hemisphere; RH = Right Hemisphere.
Simil | Block | Word tot | Word del | Story imm | Story del | Serial | Stroop | |
---|---|---|---|---|---|---|---|---|
Meningioma | ns | <0.001 | ns | 0.019 | ns | 0.003 | 0.043 | 0.002 |
LGG | ns | ns | ns | ns | 0.001 | ns | 0.047 | ns |
Small | ns | 0.001 | ns | 0.006 | 0.041 | 0.010 | 0.007 | 0.001 |
Large | ns | 0.008 | ns | ns | 0.006 | ns | ns | ns |
LH | 0.030 | 0.017 | ns | ns | 0.006 | ns | 0.008 | ns |
RH | ns | 0.003 | ns | ns | ns | 0.010 | ns | 0.002 |
Anterior | ns | <0.001 | ns | 0.049 | 0.038 | 0.012 | 0.027 | ns |
Posterior | ns | 0.041 | 0.016 | 0.022 | 0.032 | 0.010 | 0.028 | 0.031 |
“ns” indicates no statistically significant difference between the groups on a 0.05 level. Abbreviations: Simil = WAIS Similarities; Block = WAIS Block Design; Word Tot = Word List Recall Total score; Word del = Word List Recall Delayed Recall; Story imm = The Babcock story immediate recall; Story del = The Babcock Story delayed recall; Serial = Serial Seven Subtraction Test time; Stroop = Stroop Test time; LGG = Low-grade Glioma (grade I-II); LH = Left Hemisphere; RH = Right Hemisphere.
tumor volumes displayed no significant change. At the 12-month follow-up, those with small tumor volumes showed further improvement in attentional, verbal and memory functions, while the patients with large tumor volumes improved their performance across visuospatial and immediate memory domains.
At the three-month follow-up, the patients with meningioma displayed improved performance in visuospatial and delayed memory functions, with the group with LGG showing enhancement in immediate memory functions. At the 12-month follow-up, the meningioma groups exhibited further improvement in delayed memory and attentional domains, with the LGG group further improving in attentional functions.
The aims of the current study were to examine the nature of cognitive deficits in intracranial tumor patients, i.e., whether they may be local or more general in nature, as well as to delineate the ways in which characteristics of the tumor affect cognitive performance. In addition, the effects of surgical treatment on cognitive performance together with the factors associated with cognitive recovery were examined.
In this study, the tumor-induced cognitive impairment appeared diffuse affecting the majority of cognitive domains. However, specific cognitive deficits based on the location of the tumor were not found. Patients with anterior or large tumors suffered the most severe cognitive impairments before the surgical operation. Surgical operation of the tumor had recovering effect on tumor-induced cognitive impairment. Cognitive recovery was more noticeable in patients with meningioma as compared to those with LGG and also in patients with small tumors as compared to those with large tumors. The current results are consistent with previous evidence reporting intracranial tumor related cognitive impairment to be generalized in nature [
One possible explanation for the absence of clear association between the tumor location and specific type of cognitive deficit in the current study concerns the underlying neural pathology of the tumor. This seems plausible in light of previous evidence indicating that intracranial tumors cause alterations to the functional connectivity of the whole brain network when measured with magnetoencephalography [
In the current study, tumors with large volumes were associated with a greater negative impact on cognitive performance as compared to small tumors. This lends support to previous studies, in which large tumor volume and rapid growth rate were isolated as key factors underlying the resultant cognitive impairment [
The surgical operation of the tumor was associated with a recovery effect on tumor-induced cognitive impairment. However, the extent of recovery was affected by the histological type of the tumor. In the current study, the patients with meningiomas showed some degree of recovery across all cognitive domains impaired at the preoperative assessment, this being in line with a review by Meskal, et al. [
The strengths of the current study include a control group, and the design including both preoperative and postoperative neuropsychological assessments, which have been absent for the majority of existing studies on brain tumor-induced cognitive changes [
The current results have significant implications for the clinical practice. First, due to the diffuse nature of brain tumor-induced cognitive impairment, cognitive performance of the tumor patient needs to be assessed across all cognitive domains. Second, an important factor concerning the clinical practice is the time of the recovery. The cognitive recovery post-surgery that was observed in the current study commonly involved only partial recovery after three months, with ongoing recovery being evident at 12 months. This suggests that spontaneous recovery from the intracranial tumor operation will require a minimum of one year time-wise, which thus represents a crucial time window for rehabilitation.
In summary, intracranial tumors are linked to severe cognitive impairment in various cognitive domains. However, surgical operation of the tumor alleviates the extent of the impairment. Mitigation of the impairment and the extent and rate of cognitive recovery depend substantially both on type and the size of the tumor, as cognitive impairment appears more persistent with gliomas and large tumors. Merely a partial spontaneous recovery is observed in the few months following surgery, and recovery from the tumor and the surgery requires a minimum of one year time-wise. Further studies are warranted to examine how neuropsychological rehabilitation may alleviate tumor-induced cognitive impairment (specifically in frontal tumor patients), as well as the types of interactions that may exist between different tumor characteristics.
The authors would like to thank Riitta Herva for histological analyses and John Koivukangas for supervising the data acquisition at the Department of Neurosurgery, Oulu University Hospital.
The authors declare no conflicts of interest regarding the publication of this paper.
Lahti, J., Saunamäki, T., Salo, J., Niemelä, A. and Jehkonen, M. (2018) Cognitive Impairment and Recovery in Meningiomas and Low-Grade Gliomas. Journal of Behavioral and Brain Science, 8, 473-484. https://doi.org/10.4236/jbbs.2018.88029